TheInfoList

In
economics Economics () is a social science Social science is the branch A branch ( or , ) or tree branch (sometimes referred to in botany Botany, also called , plant biology or phytology, is the science of plant life and a bran ...

, inflation refers to a general progressive increase in prices of goods and services in an economy. When the general price level rises, each unit of currency buys fewer goods and services; consequently, inflation corresponds to a reduction in the
purchasing power Purchasing power is the amount of goods and services that can be purchased with a unit of currency A currency, "in circulation", from la, currens, -entis, literally meaning "running" or "traversing" in the most specific sense is money Im ...
of money. The opposite of inflation is
deflation In , deflation is a decrease in the general of goods and services. Deflation occurs when the rate falls below 0% (a negative ). Inflation reduces the value of over time, but sudden deflation increases it. This allows more goods and services t ...

, a sustained decrease in the general price level of goods and services. The common measure of inflation is the inflation rate, the annualised percentage change in a general
price index A price index (''plural'': "price indices" or "price indexes") is a normalized average (typically a weighted average) of price A price is the (usually not negative) quantity of payment or compensation given by one party to another in re ...
. Prices will not all increase at the same rates. Attaching a representative value to a set of prices is an instance of the index number problem. The
consumer price index#REDIRECT consumer price index A consumer price index measures changes in the price level of a weighted average market basket of Goods, consumer goods and Services marketing, services purchased by households. A CPI is a statistical estimate con ...
is often used for this purpose; the employment cost index is used for wages in the United States. Differential movement between consumer prices and wages constitutes a change in the
standard of living Standard of living is the level of income, comforts and services available, generally applied to a society or location, rather than to an individual. Standard of living is relevant because it is considered to contribute to an individual's quality ...
. The causes of inflation have been much discussed (see
below Below may refer to: *Earth *Ground (disambiguation) *Soil *Floor *Bottom (disambiguation) *Less than *Temperatures below freezing *Hell or underworld People with the surname *Fred Below (1926–1988), American blues drummer *Fritz von Below (1853 ...
), the consensus being that growth in the
money supply In macroeconomics, the money supply (or money stock) refers to the total volume of money held by the public at a particular point in time in an economy. There are several ways to define "money", but standard measures usually include Circulati ...
is typically the dominant causal factor. If money was perfectly neutral, inflation would have no effect on the real economy; but perfect neutrality is not generally considered believable. Effects on the real economy are severely disruptive in the cases of very high inflation and
hyperinflation In , hyperinflation is very high and typically accelerating . It quickly erodes the of the local , as the prices of all goods increase. This causes people to minimize their holdings in that currency as they usually switch to more stable forei ...

. More moderate inflation affects economies in both positive and negative ways. The negative effects include an increase in the
opportunity cost In microeconomic theory Microeconomics (from Greek prefix ''mikro-'' meaning "small" + ''economics'') is a branch of economics Economics () is the social science that studies how people interact with value; in particular, the Produ ...
of holding money, uncertainty over future inflation which may discourage investment and savings, and if inflation were rapid enough, shortages of
goods In economics Economics () is a social science Social science is the branch A branch ( or , ) or tree branch (sometimes referred to in botany Botany, also called , plant biology or phytology, is the science of plant ...
as consumers begin
hoarding Hoarding is a behavior where people or animals accumulate food or other items. Animal behavior ''Hoarding'' and ''caching'' are common in many bird Birds are a group of warm-blooded vertebrates constituting the class (biology), cl ...
out of concern that prices will increase in the future. Positive effects include reducing
unemployment Unemployment, according to the OECD The Organisation for Economic Co-operation and Development (OECD; french: Organisation de Coopération et de Développement Économiques, OCDE) is an intergovernmental economic organisation with 38&nbs ...
due to nominal wage rigidity, allowing the central bank greater freedom in carrying out
monetary policy Monetary policy is the policy adopted by the monetary authority In finance and economics, a monetary authority is the entity that manages a country’s currency and money supply, often with the objective of controlling inflation targeting, infla ...

, encouraging loans and investment instead of money hoarding, and avoiding the inefficiencies associated with deflation. Today, most economists favour a low and steady rate of inflation.Hummel, Jeffrey Rogers. "Death and Taxes, Including Inflation: the Public versus Economists" (January 2007

p. 56
Low (as opposed to zero or Deflation, negative) inflation reduces the severity of economic
recessions In economics Economics () is the social science that studies how people interact with value; in particular, the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods ...
by enabling the labor market to adjust more quickly in a downturn, and reduces the risk that a
liquidity trap A liquidity trap is a situation, described in Keynesian economics, in which, "after the rate of interest has fallen to a certain level, liquidity preference may become virtually absolute in the sense that almost everyone prefers holding cash ...
prevents
monetary policy Monetary policy is the policy adopted by the monetary authority In finance and economics, a monetary authority is the entity that manages a country’s currency and money supply, often with the objective of controlling inflation targeting, infla ...

from stabilising the economy.Escaping from a Liquidity Trap and Deflation: The Foolproof Way and Others
Lars E.O. Svensson, ''Journal of Economic Perspectives'', Volume 17, Issue 4 Fall 2003, pp. 145–166
The task of keeping the rate of inflation low and stable is usually given to monetary authorities. Generally, these monetary authorities are the
central bank A central bank, reserve bank, or monetary authority is an institution that manages the and of a or formal monetary union, and oversees their . In contrast to a , a central bank possesses a on increasing the . Most central banks also have ...

s that control monetary policy through the setting of
interest rate An interest rate is the amount of interest In and , interest is payment from a or deposit-taking financial institution to a or depositor of an amount above repayment of the (that is, the amount borrowed), at a particular rate. It is disti ...
s, by carrying out
open market operation An open market operation (OMO) is an activity by a central bank A central bank, reserve bank, or monetary authority is an institution that manages the currency and monetary policy of a State (polity), state or formal monetary union, and over ...
s and (more rarely) changing commercial bank
reserve requirements Reserve or reserves may refer to: Places * Reserve, Kansas Reserve is a city in Brown County, Kansas, Brown County, Kansas, United States. As of the 2010 United States Census, 2010 census, the city population was 84. It is located approximate ...
.

# Definition

The term ''inflation'' appeared in America in the mid-nineteenth century, “not in reference to something that happens to prices, but as something that happens to a paper currency”.Bryan, Michael F.
"On the Origin and Evolution of the Word Inflation"
''Federal Reserve Bank of Cleveland, Economic Commentary,'' 15 October 1997.
Today, however, it is understood as referring to a sustained increase in the general price level (as distinct from short-term fluctuations). The expression “price inflation” may either be synonymous with “inflation” or reflect some more restrictive definition of “price”. Changes to the wage level are described as “wage inflation” and changes to the money supply as “
monetary inflation Monetary inflation is a sustained increase in the money supply In macroeconomics, the money supply (or money stock) is the total value of money available in an economy at a point of time. There are several ways to define "money", but standa ...

”. These terms are sometimes assumed to identify the causative factor. More specific forms of inflation refer to sectors whose prices vary semi-independently from the general trend. “House price inflation” applies to changes in the
house price indexA house price index (HPI) measures the price changes of residential housing as a percentage change from some specific start date (which has HPI of 100). Methodologies commonly used to calculate a HPI are the hedonic regression (HR), simple moving ave ...
while “energy inflation” is dominated by the costs of oil and gas.

## Related concepts

Other economic concepts related to inflation include:
deflation In , deflation is a decrease in the general of goods and services. Deflation occurs when the rate falls below 0% (a negative ). Inflation reduces the value of over time, but sudden deflation increases it. This allows more goods and services t ...

a fall in the general price level;
disinflation Disinflation is a decrease in the rate of inflation – a slowdown in the rate of increase of the general price level of goods and services in a nation's gross domestic product Gross domestic product (GDP) is a money, monetary Measurement in ...
a decrease in the rate of inflation;
hyperinflation In , hyperinflation is very high and typically accelerating . It quickly erodes the of the local , as the prices of all goods increase. This causes people to minimize their holdings in that currency as they usually switch to more stable forei ...

an out-of-control inflationary spiral;
stagflation In economics Economics () is the social science that studies how people interact with value; in particular, the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods ...
a combination of inflation, slow economic growth and high unemployment;
reflationReflation is an act of stimulating the economy An economy (; ) is an area of the Production (economics), production, Distribution (economics), distribution and trade, as well as Consumption (economics), consumption of Goods (economics), goods a ...
an attempt to raise the general level of prices to counteract deflationary pressures; and
asset price inflation Asset price inflation is an economic phenomenon denoting a rise in price A price is the (usually not negative) quantity of payment or compensation given by one party to another in return for one unit of goods or services. A price is ...
a general rise in the prices of financial assets without a corresponding increase in the prices of goods or services; agflation – an advanced increase in the price for food and industrial agricultural crops when compared with the general rise in prices.

# Theoretical background

## Classical economics

By the nineteenth century, economists categorised three separate factors that cause a rise or fall in the price of goods: a change in the ''
value Value or values may refer to: * Value (ethics) In ethics Ethics or moral philosophy is a branch of philosophy Philosophy (from , ) is the study of general and fundamental questions, such as those about Metaphysics, existence, reason, E ...
'' or production costs of the good, a change in the ''price of money'' which then was usually a fluctuation in the
commodity In economics Economics () is a social science Social science is the branch A branch ( or , ) or tree branch (sometimes referred to in botany Botany, also called , plant biology or phytology, is the science of plan ...
price of the metallic content in the currency, and ''currency depreciation'' resulting from an increased supply of currency relative to the quantity of redeemable metal backing the currency. Following the proliferation of private
banknote A banknote (often known as a bill (in the US and Canada), paper money, or simply a note) is a type of negotiable promissory note A promissory note, sometimes referred to as a note payable, is a legal instrument ''Legal instrument'' is a ...
currency printed during the
American Civil War The American Civil War (also known by other names Other most often refers to: * Other (philosophy), a concept in psychology and philosophy Other or The Other may also refer to: Books * The Other (Tryon novel), ''The Other'' (Tryon nove ...
, the term "inflation" started to appear as a direct reference to the ''currency depreciation'' that occurred as the quantity of redeemable banknotes outstripped the quantity of metal available for their redemption. At that time, the term inflation referred to the
devaluation In macroeconomics Macroeconomics (from the Greek prefix ''makro-'' meaning "large" + ''economics'') is a branch of economics Economics () is the social science that studies how people interact with value; in particular, the Production ( ...
of the currency, and not to a rise in the price of goods. This relationship between the over-supply of banknotes and a resulting
depreciation In accountancy, depreciation refers to two aspects of the same concept: first, the actual decrease of fair value of an asset, such as the decrease in value of factory equipment each year as it is used and wear, and second, the allocation in a ...

in their value was noted by earlier classical economists such as
David Hume David Hume (; born David Home; 7 May 1711 NS (26 April 1711 OS) – 25 August 1776) Cranston, Maurice, and Thomas Edmund Jessop. 2020 999999 or triple nine most often refers to: * 999 (emergency telephone number) 250px, A sign on a beach ...

and
David Ricardo David Ricardo (18 April 1772 – 11 September 1823) was a British political economist, one of the most influential of the classical economists along with Thomas Malthus Thomas Robert Malthus (; 13/14 February 1766 – 23 December 1834) w ...

, who would go on to examine and debate what effect a currency devaluation (later termed ''
monetary inflation Monetary inflation is a sustained increase in the money supply In macroeconomics, the money supply (or money stock) is the total value of money available in an economy at a point of time. There are several ways to define "money", but standa ...

'') has on the price of goods (later termed ''price inflation'', and eventually just ''inflation'').

# History

Historically, large infusions of gold or silver into an economy had led to inflation. For instance, when silver was used as currency, the government could collect silver coins, melt them down, mix them with other metals such as copper or lead and reissue them at the same
nominal value In economics Economics () is the social science that studies how people interact with value; in particular, the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods ...
, a process known as
debasement A debasement of coinage is the practice of lowering the intrinsic value of coin A coin is a small, flat, (usually, depending on the country or value) round piece of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon ...
. At the ascent of
Nero Nero ( ; full name: Nero Claudius Caesar Augustus Germanicus; 15 December AD 37 – 9 June AD 68) was the fifth emperor of Rome. He was Adoption in Ancient Rome, adopted by the Roman emperor Claudius at the age of 13 and s ...

as Roman emperor in AD 54, the
denarius The denarius (, dēnāriī ) was the standard Roman Roman or Romans most often refers to: *, the capital city of Italy *, Roman civilization from 8th century BC to 5th century AD *, the people of ancient Rome *', shortened to ''Romans'', a ...
contained more than 90% silver, but by the 270s hardly any silver was left. By diluting the silver with other metals, the government could issue more coins without increasing the amount of silver used to make them. When the cost of each coin is lowered in this way, the government profits from an increase in
seigniorage Seigniorage , also spelled seignorage or seigneurage (from the Old French ''seigneuriage'', "right of the lord (''seigneur'') to mint money"), is the difference between the value of money and the cost to produce and distribute it. The term can be ap ...
. This practice would increase the money supply but at the same time the relative value of each coin would be lowered. As the relative value of the coins becomes lower, consumers would need to give more coins in exchange for the same goods and services as before. These goods and services would experience a price increase as the value of each coin is reduced. The adoption of
fiat currency Fiat money (from la, fiat, ) is a type of money that is not backed by any commodity such as gold or silver, and typically declared by a decree A decree is a rule of law usually issued by a head of state A head of state (or chief of sta ...
by many countries, from the 18th century onwards, made much larger variations in the supply of money possible. Rapid increases in the
money supply In macroeconomics, the money supply (or money stock) refers to the total volume of money held by the public at a particular point in time in an economy. There are several ways to define "money", but standard measures usually include Circulati ...
have taken place a number of times in countries experiencing political crises, producing
hyperinflation In , hyperinflation is very high and typically accelerating . It quickly erodes the of the local , as the prices of all goods increase. This causes people to minimize their holdings in that currency as they usually switch to more stable forei ...

s episodes of extreme inflation rates much higher than those observed in earlier periods of
commodity money Commodity money is money Money is any item or verifiable record that is generally accepted as payment for goods and services and repayment of debts, such as taxes, in a particular country or socio-economic context. The main functions of m ...
. The
hyperinflation in the Weimar Republic Hyperinflation 400px, Hyperinflation in Venezuela represented by the time it would take for money to lose 90% of its value (301-day rolling average, inverted logarithmic scale). In economics, hyperinflation is very high and typically accele ...
of Germany is a notable example. Currently, the hyperinflation in
Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continent A continent is any of several large l ...

is the highest in the world, with an annual inflation rate of 833,997% as of October 2018. However, since the 1980s, inflation has been held low and stable in countries with independent
central bank A central bank, reserve bank, or monetary authority is an institution that manages the and of a or formal monetary union, and oversees their . In contrast to a , a central bank possesses a on increasing the . Most central banks also have ...

s. This has led to a moderation of the
business cycle The business cycle, also known as the economic cycle or trade cycle, are the fluctuations of gross domestic product Gross domestic product (GDP) is a monetary Image:National-Debt-Gillray.jpeg, In a 1786 James Gillray caricature, the pl ...

and a reduction in variation in most macroeconomic indicators - an event known as the
Great Moderation The Great Moderation is a period starting from the mid-1980s until 2007 characterized by the reduction in the volatility of business cycle The business cycle, also known as the economic cycle or trade cycle, are the fluctuations of gross domes ...
.

# Historical inflationary periods

Rapid increases in the quantity of money or in the overall
money supply In macroeconomics, the money supply (or money stock) refers to the total volume of money held by the public at a particular point in time in an economy. There are several ways to define "money", but standard measures usually include Circulati ...
have occurred in many different societies throughout history, changing with different forms of money used.

## Ancient China

Song Dynasty The Song dynasty (; ; 960–1279) was an imperial dynasty of China that began in 960 and lasted until 1279. The dynasty was founded by Emperor Taizu of Song Emperor Taizu of Song (21 March 927 – 14 November 976), personal name Zhao Kua ...
China introduced the practice of printing paper money to create
fiat currency Fiat money (from la, fiat, ) is a type of money that is not backed by any commodity such as gold or silver, and typically declared by a decree A decree is a rule of law usually issued by a head of state A head of state (or chief of sta ...
. During the Mongol
Yuan Dynasty The Yuan dynasty (), officially the Great Yuan (; xng, , , literally "Great Yuan State"), was a successor state Successor is someone who, or something which succeeds or comes after (see success and succession) Film and TV * ''The Succ ...
, the government spent a great deal of money fighting costly wars, and reacted by printing more money, leading to inflation. Fearing the inflation that plagued the Yuan dynasty, the
Ming Dynasty The Ming dynasty (), officially the Great Ming, was the Dynasties in Chinese history, ruling dynasty of China from 1368 to 1644 following the collapse of the Mongol Empire, Mongol-led Yuan dynasty. The Ming dynasty was the last imperial dynas ...

initially rejected the use of paper money, and reverted to using copper coins.

## Medieval Egypt

During the Malian king
Mansa Musa Musa I (c. 1280 – ), or Mansa Musa, was the ninth ''Mansa (title), Mansa'' of the Mali Empire, one of the most powerful Islamic West African states. At the time of Musa's ascension to the throne, Mali in large part consisted of the territo ...

's
hajj The Hajj (; ar, حَجّ ' "wikt:pilgrimage, ''pilgrimage''"; sometimes also spelled Hadj, Hadji or Haj in English) is an annual Islamic pilgrimage to Mecca, Saudi Arabia, the Holiest sites in Islam, holiest city for Muslims. Hajj is a Far ...
to
Mecca Mecca, officially Makkah al-Mukarramah ( ) and commonly shortened to Makkah ( ),Quran 48:22 ' () is a city and administrative center of the Mecca Province of Saudi Arabia, and the Holiest sites in Islam, holiest city in Islam. It is inland ...

in 1324, he was reportedly accompanied by a
camel train File:BosraMosaicCamels.png, 300px, Ancient Roman mosaic depicting a merchant leading a camel train. Bosra, Syria Image:Camels in Jordan valley (4568207363).jpg, 300px, Camels convoy in the Jordan Rift Valley, May 2010. A camel train or caravan is ...
that included thousands of people and nearly a hundred camels. When he passed through
Cairo Cairo ( ; ar, القاهرة, al-Qāhirah, , Coptic Coptic may refer to: Afro-Asia * Copts, an ethnoreligious group mainly in the area of modern Egypt but also in Sudan and Libya * Coptic language, a Northern Afro-Asiatic language spoken in E ...

, he spent or gave away so much gold that it depressed its price in Egypt for over a decade, reducing its purchasing power. A contemporary Arab historian remarked about Mansa Musa's visit:

## "Price revolution" in Western Europe

From the second half of the 15th century to the first half of the 17th, Western Europe experienced a major inflationary cycle referred to as the "
price revolution The Price Revolution, sometimes known as the Spanish Price Revolution, was a series of economic events that occurred between the second half of the 15th century and the first half of the 17th century, and most specifically linked to the high rate of ...
", with prices on average rising perhaps sixfold over 150 years. This is often attributed to the influx of gold and silver from the
New World The "New World" is a term for the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. 33: " 6c:_from__...
_into_Habsburg_Spain,_with_wider_availability_of_ 6c:_from__...
_into_Habsburg_Spain,_with_wider_availability_of_Silver_coin">silver_ Silver_is_a_chemical_element_ In_chemistry,_an_element_is_a_pure_Chemical_substance,_substance_consisting_only_of_atoms_that_all_have_the_same_numbers_of_protons_in_their_atomic_nucleus,_nuclei._Unlike_chemical_compounds,_chemical_ele_...
_in_previously_Commercial_revolution.html" ;"title="Silver_coin.html" "title="Habsburg_Spain.html" ;"title="6c: from ...
into Habsburg Spain">6c: from ...
into Habsburg Spain, with wider availability of Silver coin">silver Silver is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical ele ...
in previously Commercial revolution">cash-starved Europe causing widespread inflation. European population rebound from the Black Death began before the arrival of New World metal, and may have began a process of inflation that New World silver compounded later in the 16th century.

# Measures

Since there are many possible measures of the price level, there are many possible measures of price inflation. Most frequently, the term "inflation" refers to a rise in a broad price index representing the overall price level for goods and services in the economy. The
Consumer Price Index#REDIRECT consumer price index A consumer price index measures changes in the price level of a weighted average market basket of Goods, consumer goods and Services marketing, services purchased by households. A CPI is a statistical estimate con ...
(CPI), the
Personal consumption expenditures price index The PCE price index (PCEPI), also referred to as the PCE deflator, PCE price deflator, or the Implicit Price Deflator for Personal Consumption Expenditures (IPD for PCE) by the BEA, and as the Chain-type Price Index for Personal Consumption Expen ...
(PCEPI) and the
GDP deflator In economics Economics () is a social science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services. Economics focuses on the behaviou ...
are some examples of broad price indices. However, "inflation" may also be used to describe a rising price level within a narrower set of assets, goods or services within the economy, such as
commodities In economics, a commodity is an economic goods, good, usually a resource, that has full or substantial fungibility: that is, the Market (economics), market treats instances of the good as equivalent or nearly so with no regard to who Production ...
(including food, fuel, metals),
tangible asset In financial accounting Financial accounting is the field of accounting Accounting or Accountancy is the measurement, processing, and communication of financial and non financial information about economic entity, economic entities such as ...
s (such as real estate),
financial asset A financial asset is a non-physical asset In financial accounting Financial accounting is the field of accounting Accounting or Accountancy is the measurement, processing, and communication of financial and non financial information abou ...
s (such as stocks, bonds), services (such as entertainment and health care), or
labor Labour or labor may refer to: * , the delivery of a baby * , or work ** , physical work ** , a socioeconomic relationship between a worker and an employer Literature * , an American quarterly on the history of the labor movement * ', an academic ...
. Although the values of capital assets are often casually said to "inflate," this should not be confused with inflation as a defined term; a more accurate description for an increase in the value of a capital asset is appreciation. The Reuters-CRB Index (CCI), the
Producer Price Index A producer price index (PPI) is a price index A price index (''plural'': "price indices" or "price indexes") is a normalized average (typically a weighted average) of price A price is the (usually not negative) quantity of payment or co ...

, and Employment Cost Index (ECI) are examples of narrow price indices used to measure price inflation in particular sectors of the economy.
Core inflation Core inflation represents the long run trend in the price level. In measuring long run inflation In economics Economics () is the social science that studies how people interact with value; in particular, the Production (economic ...
is a measure of inflation for a subset of consumer prices that excludes food and energy prices, which rise and fall more than other prices in the short term. The
Federal Reserve Board The Board of Governors of the Federal Reserve System, commonly known as the Federal Reserve Board, is the main governing body of the Federal Reserve, Federal Reserve System. It is charged with overseeing the Federal Reserve Banks and with helping i ...
pays particular attention to the core inflation rate to get a better estimate of long-term future inflation trends overall. The inflation rate is most widely calculated by determining the movement or change in a price index, typically the
consumer price index#REDIRECT consumer price index A consumer price index measures changes in the price level of a weighted average market basket of Goods, consumer goods and Services marketing, services purchased by households. A CPI is a statistical estimate con ...
. The inflation rate is the percentage change of a price index over time. The Retail Prices Index is also a measure of inflation that is commonly used in the United Kingdom. It is broader than the CPI and contains a larger basket of goods and services. To illustrate the method of calculation, in January 2007, the U.S. Consumer Price Index was 202.416, and in January 2008 it was 211.080. The formula for calculating the annual percentage rate inflation in the CPI over the course of the year is: $\left\left(\frac\right\right)\times100\%=4.28\%$ The resulting inflation rate for the CPI in this one-year period is 4.28%, meaning the general level of prices for typical U.S. consumers rose by approximately four percent in 2007. Other widely used price indices for calculating price inflation include the following: * (PPIs) which measures average changes in prices received by domestic producers for their output. This differs from the CPI in that price subsidization, profits, and taxes may cause the amount received by the producer to differ from what the consumer paid. There is also typically a delay between an increase in the PPI and any eventual increase in the CPI. Producer price index measures the pressure being put on producers by the costs of their raw materials. This could be "passed on" to consumers, or it could be absorbed by profits, or offset by increasing productivity. In India and the United States, an earlier version of the PPI was called the Wholesale price index. * Commodity price indices, which measure the price of a selection of commodities. In the present commodity price indices are weighted by the relative importance of the components to the "all in" cost of an employee. * Core price indices: because food and oil prices can change quickly due to changes in
supply and demand In microeconomics Microeconomics is a branch of that studies the behavior of individuals and in making decisions regarding the allocation of and the interactions among these individuals and firms. Microeconomics focuses on the study ...

conditions in the food and oil markets, it can be difficult to detect the long run trend in price levels when those prices are included. Therefore, most statistical agencies also report a measure of 'core inflation', which removes the most volatile components (such as food and oil) from a broad price index like the CPI. Because core inflation is less affected by short run supply and demand conditions in specific markets,
central bank A central bank, reserve bank, or monetary authority is an institution that manages the and of a or formal monetary union, and oversees their . In contrast to a , a central bank possesses a on increasing the . Most central banks also have ...

s rely on it to better measure the inflationary impact of current
monetary policy Monetary policy is the policy adopted by the monetary authority In finance and economics, a monetary authority is the entity that manages a country’s currency and money supply, often with the objective of controlling inflation targeting, infla ...

. Other common measures of inflation are: *
GDP deflator In economics Economics () is a social science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services. Economics focuses on the behaviou ...
is a measure of the price of all the goods and services included in gross domestic product (GDP). The US Commerce Department publishes a deflator series for US GDP, defined as its nominal GDP measure divided by its real GDP measure. ∴ $\mbox = \frac$ * Regional inflation The Bureau of Labor Statistics breaks down CPI-U calculations down to different regions of the US. * Historical inflation Before collecting consistent econometric data became standard for governments, and for the purpose of comparing absolute, rather than relative standards of living, various economists have calculated imputed inflation figures. Most inflation data before the early 20th century is imputed based on the known costs of goods, rather than compiled at the time. It is also used to adjust for the differences in real standard of living for the presence of technology. *
Asset price inflation Asset price inflation is an economic phenomenon denoting a rise in price A price is the (usually not negative) quantity of payment or compensation given by one party to another in return for one unit of goods or services. A price is ...
is an undue increase in the prices of real or financial assets, such as
stock In finance, stock (also capital stock) consists of all of the shares In financial markets A financial market is a market in which people trade financial securities and derivatives at low transaction costs. Some of the securities i ...

(equity) and real estate. While there is no widely accepted index of this type, some central bankers have suggested that it would be better to aim at stabilizing a wider general price level inflation measure that includes some asset prices, instead of stabilizing CPI or core inflation only. The reason is that by raising interest rates when stock prices or real estate prices rise, and lowering them when these asset prices fall, central banks might be more successful in avoiding bubbles and crashes in asset prices.

## Issues in measuring

Measuring inflation in an economy requires objective means of differentiating changes in nominal prices on a common set of goods and services, and distinguishing them from those price shifts resulting from changes in value such as volume, quality, or performance. For example, if the price of a can of corn changes from $0.90 to$1.00 over the course of a year, with no change in quality, then this price difference represents inflation. This single price change would not, however, represent general inflation in an overall economy. To measure overall inflation, the price change of a large "basket" of representative goods and services is measured. This is the purpose of a
price index A price index (''plural'': "price indices" or "price indexes") is a normalized average (typically a weighted average) of price A price is the (usually not negative) quantity of payment or compensation given by one party to another in re ...
, which is the combined price of a "basket" of many goods and services. The combined price is the sum of the weighted prices of items in the "basket". A weighted price is calculated by multiplying the
unit price A product's average price is the result of dividing the product's total sales revenue by the total units sold. When one product is sold in variants, such as bottle sizes, managers must define "comparable" units. Average prices can be calculated by ...
of an item by the number of that item the average consumer purchases. Weighted pricing is a necessary means to measuring the impact of individual unit price changes on the economy's overall inflation. The
Consumer Price Index#REDIRECT consumer price index A consumer price index measures changes in the price level of a weighted average market basket of Goods, consumer goods and Services marketing, services purchased by households. A CPI is a statistical estimate con ...
, for example, uses data collected by surveying households to determine what proportion of the typical consumer's overall spending is spent on specific goods and services, and weights the average prices of those items accordingly. Those weighted average prices are combined to calculate the overall price. To better relate price changes over time, indexes typically choose a "base year" price and assign it a value of 100. Index prices in subsequent years are then expressed in relation to the base year price. While comparing inflation measures for various periods one has to take into consideration the base effect as well. Inflation measures are often modified over time, either for the relative weight of goods in the basket, or in the way in which goods and services from the present are compared with goods and services from the past. Basket weights are updated regularly, usually every year, to adapt to changes in consumer behavior. Sudden changes in consumer behavior can still introduce a weighting bias in inflation measurement. For example, during the COVID-19 pandemic it has been shown that the basket of goods and services was no longer representative of consumption during the crisis, as numerous goods and services could no longer be consumed due to government containment measures (“lock-downs”). Over time, adjustments are also made to the type of goods and services selected to reflect changes in the sorts of goods and services purchased by 'typical consumers'. New products may be introduced, older products disappear, the quality of existing products may change, and consumer preferences can shift. Both the sorts of goods and services which are included in the "basket" and the weighted price used in inflation measures will be changed over time to keep pace with the changing marketplace. Different segments of the population may naturally consume different "baskets" of goods and services and may even experience different inflation rates. It is argued that companies have put more innovation into bringing down prices for wealthy families than for poor families. Inflation numbers are often
seasonally adjusted Seasonal adjustment or deseasonalization is a statistical method for removing the Seasonality, seasonal component of a time series. It is usually done when wanting to analyse the trend, and cyclical deviations from trend, of a time series independen ...
to differentiate expected cyclical cost shifts. For example, home heating costs are expected to rise in colder months, and seasonal adjustments are often used when measuring for inflation to compensate for cyclical spikes in energy or fuel demand. Inflation numbers may be averaged or otherwise subjected to statistical techniques to remove statistical noise and volatility of individual prices. When looking at inflation, economic institutions may focus only on certain kinds of prices, or ''special indices'', such as the
core inflation Core inflation represents the long run trend in the price level. In measuring long run inflation In economics Economics () is the social science that studies how people interact with value; in particular, the Production (economic ...
index which is used by central banks to formulate
monetary policy Monetary policy is the policy adopted by the monetary authority In finance and economics, a monetary authority is the entity that manages a country’s currency and money supply, often with the objective of controlling inflation targeting, infla ...

. Most inflation indices are calculated from weighted averages of selected price changes. This necessarily introduces distortion, and can lead to legitimate disputes about what the true inflation rate is. This problem can be overcome by including all available price changes in the calculation, and then choosing the
median In statistics Statistics is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, industrial, or social problem, it is conventional to begin wi ...

value. In some other cases, governments may intentionally report false inflation rates; for instance, during the presidency of
Cristina Kirchner Cristina is a female given name and may refer to: * Cristina (singer), (Cristina Monet-Palaci), American singer * Cristina D'Avena (born 1964), Italian singer and actress * Cristina Bazgan, French computer scientist * Cristina Boiț, Romanian discu ...
(2007–2015) the
government of Argentina A government is the system or group of people governing an organized community, generally a State (polity), state. In the case of its broad associative definition, government normally consists of legislature, Executive (government), ex ...
was criticised for manipulating economic data, such as inflation and GDP figures, for political gain and to reduce payments on its inflation-indexed debt.

## Inflation expectations

Inflation expectations or expected inflation is the rate of inflation that is anticipated for some period of time in the foreseeable future. There are two major approaches to modeling the formation of inflation expectations.
Adaptive expectations In economics Economics () is the social science that studies how people interact with value; in particular, the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods an ...
models them as a weighted average of what was expected one period earlier and the actual rate of inflation that most recently occurred.
Rational expectations In economics, "rational expectations" are model-consistent expectations, in that agent (economics), agents inside the model (economics), model are assumed to "know the model" and on average take the model's predictions as valid. Rational expectat ...
models them as unbiased, in the sense that the expected inflation rate is not systematically above or systematically below the inflation rate that actually occurs. A long-standing survey of inflation expectations is the University of Michigan survey. Inflation expectations affect the economy in several ways. They are more or less built into
nominal interest rateIn finance and economics, the nominal interest rate or nominal rate of interest is either of two distinct things: # the rate of interest In finance Finance is the study of financial institutions, financial markets and how they operate within ...
s, so that a rise (or fall) in the expected inflation rate will typically result in a rise (or fall) in nominal interest rates, giving a smaller effect if any on
real interest rate The real interest rate is the rate of interest an investor, saver or lender receives (or expects to receive) after allowing for inflation. It can be described more formally by the Fisher equation In financial mathematicsMathematical finance, also ...
s. In addition, higher expected inflation tends to be built into the rate of wage increases, giving a smaller effect if any on the changes in
real wages US net productivity compared to real wages. Real wages are wages adjusted for inflation In economics Economics () is the social science that studies how people interact with value; in particular, the Production (economics), produc ...
. Moreover, the response of inflationary expectations to monetary policy can influence the division of the effects of policy between inflation and unemployment (see Monetary policy credibility).

# Causes

Historically, a great deal of economic literature was concerned with the question of what causes inflation and what effect it has. There were different schools of thought as to the causes of inflation. Most can be divided into two broad areas: quality theories of inflation and quantity theories of inflation. The quality theory of inflation rests on the expectation of a seller accepting currency to be able to exchange that currency at a later time for goods they desire as a buyer. The quantity theory of money, quantity theory of inflation rests on the quantity equation of money that relates the money supply, its velocity of money, velocity, and the nominal value of exchanges. Currently, the quantity theory of money is widely accepted as an accurate model of inflation in the long run. Consequently, there is now broad agreement among economists that in the long run, the inflation rate is essentially dependent on the growth rate of the money supply relative to the growth of the economy. However, in the short and medium term inflation may be affected by supply and demand pressures in the economy, and influenced by the relative elasticity of wages, prices and interest rates. The question of whether the short-term effects last long enough to be important is the central topic of debate between monetarist and Keynesian economists. In monetarism prices and wages adjust quickly enough to make other factors merely marginal behavior on a general trend-line. In the Keynesian economics, Keynesian view, prices and wages adjust at different rates, and these differences have enough effects on real output to be "long term" in the view of people in an economy.

## Keynesian view

Keynesian economics proposes that changes in the money supply do not directly affect prices in the short run, and that visible inflation is the result of demand pressures in the economy expressing themselves in prices. There are three major sources of inflation, as part of what Robert J. Gordon calls the "triangle model": * ''Demand-pull inflation'' is caused by increases in aggregate demand due to increased private and government spending, etc. Demand inflation encourages economic growth since the excess demand and favourable market conditions will stimulate investment and expansion. * ''Cost-push inflation'', also called "supply shock inflation," is caused by a drop in aggregate supply (potential output). This may be due to natural disasters, or increased prices of inputs. For example, a sudden decrease in the supply of oil, leading to increased oil prices, can cause cost-push inflation. Producers for whom oil is a part of their costs could then pass this on to consumers in the form of increased prices. Another example stems from unexpectedly high insured losses, either legitimate (catastrophes) or fraudulent (which might be particularly prevalent in times of recession). High inflation can prompt employees to demand rapid wage increases, to keep up with consumer prices. In the cost-push theory of inflation, rising wages in turn can help fuel inflation. In the case of collective bargaining, wage growth will be set as a function of inflationary expectations, which will be higher when inflation is high. This can cause a price/wage spiral, wage spiral. In a sense, inflation begets further inflationary expectations, which beget further inflation. * Built-in inflation is induced by adaptive expectations, and is often linked to the "price/wage spiral". It involves workers trying to keep their wages up with prices (above the rate of inflation), and firms passing these higher labor costs on to their customers as higher prices, leading to a feedback loop. Built-in inflation reflects events in the past, and so might be seen as hangover inflation. Demand-pull theory states that inflation accelerates when aggregate demand increases beyond the ability of the economy to produce (its potential output). Hence, any factor that increases aggregate demand can cause inflation. However, in the long run, aggregate demand can be held above productive capacity only by increasing the quantity of money in circulation faster than the real growth rate of the economy. Another (although much less common) cause can be a rapid decline in the ''demand'' for money, as happened in Europe during the Black Death, or in the Greater East Asia Co-Prosperity Sphere, Japanese occupied territories just before the defeat of Japan in 1945. The effect of money on inflation is most obvious when governments finance spending in a crisis, such as a civil war, by printing money excessively. This sometimes leads to
hyperinflation In , hyperinflation is very high and typically accelerating . It quickly erodes the of the local , as the prices of all goods increase. This causes people to minimize their holdings in that currency as they usually switch to more stable forei ...

, a condition where prices can double in a month or even daily. The money supply is also thought to play a major role in determining moderate levels of inflation, although there are differences of opinion on how important it is. For example, Monetarism, monetarist economists believe that the link is very strong; Keynesian economists, by contrast, typically emphasize the role of aggregate demand in the economy rather than the money supply in determining inflation. That is, for Keynesians, the money supply is only one determinant of aggregate demand. Some Keynesian economists also disagree with the notion that central banks fully control the money supply, arguing that central banks have little control, since the money supply adapts to the demand for bank credit issued by commercial banks. This is known as the theory of endogenous money, and has been advocated strongly by post-Keynesians as far back as the 1960s. This position is not universally accepted banks create money by making loans, but the aggregate volume of these loans diminishes as real interest rates increase. Thus, central banks can influence the money supply by making money cheaper or more expensive, thus increasing or decreasing its production. A fundamental concept in inflation analysis is the relationship between inflation and unemployment, called the Phillips curve. This model suggests that there is a trade-off between price stability and employment. Therefore, some level of inflation could be considered desirable to minimize unemployment. The Phillips curve model described the U.S. experience well in the 1960s but failed to describe the 1973–75 recession, stagflation experienced in the 1970s. Thus, modern macroeconomics describes inflation using a Phillips curve that is able to shift due to such matters as supply shocks and structural inflation. The former refers to such events like the 1973 oil crisis, while the latter refers to the price/wage spiral and Adaptive expectations, inflationary expectations implying that inflation is the new normal. Thus, the Phillips curve represents only the demand-pull component of the triangle model. Another concept of note is the potential output (sometimes called the "natural gross domestic product"), a level of GDP, where the economy is at its optimal level of production given institutional and natural constraints. (This level of output corresponds to the Non-Accelerating Inflation Rate of Unemployment, NAIRU, or the "natural" rate of unemployment or the full-employment unemployment rate.) If GDP exceeds its potential (and unemployment is below the NAIRU), the theory says that inflation will ''accelerate'' as suppliers increase their prices and built-in inflation worsens. If GDP falls below its potential level (and unemployment is above the NAIRU), inflation will ''decelerate'' as suppliers attempt to fill excess capacity, cutting prices and undermining built-in inflation. However, one problem with this theory for policy-making purposes is that the exact level of potential output (and of the NAIRU) is generally unknown and tends to change over time. Inflation also seems to act in an asymmetric way, rising more quickly than it falls. It can change because of policy: for example, high unemployment under British Prime Minister Margaret Thatcher might have led to a rise in the NAIRU (and a fall in potential) because many of the unemployed found themselves as Structural unemployment, structurally unemployed, unable to find jobs that fit their skills. A rise in structural unemployment implies that a smaller percentage of the labor force can find jobs at the NAIRU, where the economy avoids crossing the threshold into the realm of accelerating inflation.

### Unemployment

A connection between inflation and unemployment has been drawn since the emergence of large scale unemployment in the 19th century, and connections continue to be drawn today. However, the unemployment rate generally only affects inflation in the short-term but not the long-term.Chang, R. (1997
"Is Low Unemployment Inflationary?"
''Federal Reserve Bank of Atlanta Economic Review'' 1Q97:4–13
In the long term, the velocity of money is far more predictive of inflation than low unemployment.Oliver Hossfeld (2010
"US Money Demand, Monetary Overhang, and Inflation Prediction"
''International Network for Economic Research'' working paper no. 2010.4
In Marxian economics, the unemployed serve as a reserve army of labor, which restrain wage inflation. In the 20th century, similar concepts in Keynesian economics include the NAIRU (Non-Accelerating Inflation Rate of Unemployment) and the Phillips curve.

## Monetarist view

Monetarists believe the most significant factor influencing inflation or deflation is how fast the money supply grows or shrinks. They consider fiscal policy, or government spending and taxation, as ineffective in controlling inflation. The monetarist economist Milton Friedman famously stated, ''"Inflation is always and everywhere a monetary phenomenon."'' Monetarists assert that the empirical study of monetary history shows that inflation has always been a monetary phenomenon. The quantity theory of money, simply stated, says that any change in the amount of money in a system will change the price level. This theory begins with the equation of exchange: :$MV = PQ$ where :$M$ is the nominal quantity of money; :$V$ is the velocity of money in final expenditures; :$P$ is the general price level; :$Q$ is an index of the real versus nominal value (economics), real value of final expenditures; In this formula, the general price level is related to the level of real economic activity (''Q''), the quantity of money (''M'') and the velocity of money (''V''). The formula is an identity because the velocity of money (''V'') is defined to be the ratio of final nominal expenditure ($PQ$) to the quantity of money (''M''). Monetarists assume that the velocity of money is unaffected by monetary policy (at least in the long run), and the real value of output is determined in the long run by the productive capacity of the economy. Under these assumptions, the primary driver of the change in the general price level is changes in the quantity of money. With exogenous velocity (that is, velocity being determined externally and not being influenced by monetary policy), the money supply determines the value of nominal output (which equals final expenditure) in the short run. In practice, velocity is not exogenous in the short run, and so the formula does not necessarily imply a stable short-run relationship between the money supply and nominal output. However, in the long run, changes in velocity are assumed to be determined by the evolution of the payments mechanism. If velocity is relatively unaffected by monetary policy, the long-run rate of increase in prices (the inflation rate) is equal to the long-run growth rate of the money supply plus the exogenous long-run rate of velocity growth minus the long run growth rate of real output.

### Effect of economic growth

If economic growth matches the growth of the money supply, inflation should not occur when all else is equal. A large variety of factors can affect the rate of both. For example, investment in Stock market, market production, infrastructure, education, and preventive health care can all grow an economy in greater amounts than the investment spending.

## Rational expectations theory

Rational expectations theory holds that economic actors look rationally into the future when trying to maximize their well-being, and do not respond solely to immediate opportunity costs and pressures. In this view, while generally grounded in monetarism, future expectations and strategies are important for inflation as well. A core assertion of rational expectations theory is that actors will seek to "head off" central-bank decisions by acting in ways that fulfill predictions of higher inflation. This means that central banks must establish their credibility in fighting inflation, or economic actors will make bets that the central bank will expand the money supply rapidly enough to prevent recession, even at the expense of exacerbating inflation. Thus, if a central bank has a reputation as being "soft" on inflation, when it announces a new policy of fighting inflation with restrictive monetary growth economic agents will not believe that the policy will persist; their inflationary expectations will remain high, and so will inflation. On the other hand, if the central bank has a reputation of being "tough" on inflation, then such a policy announcement will be believed and inflationary expectations will come down rapidly, thus allowing inflation itself to come down rapidly with minimal economic disruption.

## Heterodox views

There are also other theories about inflation that are no longer accepted by mainstream economics, mainstream economists.

### Austrian view

The Austrian School stresses that inflation is not uniform over all assets, goods, and services. Inflation depends on differences in markets and on where newly created money and credit enter the economy. Ludwig von Mises said that inflation should refer to an increase in the quantity of money, that is not offset by a corresponding increase in the need for money, and that price inflation will necessarily follow, always leaving a poorer nation.The Theory of Money and Credit, Mises (1912, [1981], p. 272)

### Real bills doctrine

The real bills doctrine asserts that banks should issue their money in exchange for short-term real bills of adequate value. As long as banks only issue a dollar in exchange for assets worth at least a dollar, the issuing bank's assets will naturally move in step with its issuance of money, and the money will hold its value. Should the bank fail to get or maintain assets of adequate value, then the bank's money will lose value, just as any financial security will lose value if its asset backing diminishes. The real bills doctrine (also known as the backing theory) thus asserts that inflation results when money outruns its issuer's assets. The quantity theory of money, in contrast, claims that inflation results when money outruns the economy's production of goods. Currency and banking schools of economics argue the RBD, that banks should also be able to issue currency against bills of trading, which is "real bills" that they buy from merchants. This theory was important in the 19th century in debates between "Banking" and "Currency" schools of monetary soundness, and in the formation of the Federal Reserve. In the wake of the collapse of the international gold standard post 1913, and the move towards deficit financing of government, RBD has remained a minor topic, primarily of interest in limited contexts, such as currency boards. It is generally held in ill repute today, with Frederic Mishkin, a governor of the Federal Reserve going so far as to say it had been "completely discredited." The debate between currency, or quantity theory, and the British Banking School, banking schools during the 19th century prefigures current questions about the credibility of money in the present. In the 19th century, the banking schools had greater influence in policy in the United States and Great Britain, while the British Currency School, currency schools had more influence "on the continent", that is in non-British countries, particularly in the Latin Monetary Union and the earlier Scandinavia monetary union. In 2019 monetary historians Thomas M. Humphrey and Richard H. Timberlake published "Gold, the Real Bills Doctrine, and the Fed: Sources of Monetary Disorder 1922-1938".

# Effects of inflation

## General effect

Inflation is the decrease in the purchasing power of a currency. That is, when the general level of prices rise, each monetary unit can buy fewer goods and services in aggregate. The impact of inflation differs on different sectors of the economy, with some sectors being adversely impacted while others benefitting. For example, with inflation, those segments in society which own physical assets, such as property, stock etc., benefit from the price/value of their holdings going up, when those who seek to acquire them will need to pay more for them. Their ability to do so will depend on the degree to which their income is fixed. For example, increases in payments to workers and pensioners often lag behind inflation, and for some people income is fixed. Also, individuals or institutions with cash assets will experience a decline in the purchasing power of the cash. Increases in the price level (inflation) erode the real value of money (the functional currency) and other items with an underlying monetary nature. Debtors who have debts with a fixed nominal rate of interest will see a reduction in the "real" interest rate as the inflation rate rises. The real interest on a loan is the nominal rate minus the inflation rate. The formula ''R = N-I'' approximates the correct answer as long as both the nominal interest rate and the inflation rate are small. The correct equation is ''r = n/i'' where ''r'', ''n'' and ''i'' are expressed as ratios (e.g. 1.2 for +20%, 0.8 for −20%). As an example, when the inflation rate is 3%, a loan with a nominal interest rate of 5% would have a real interest rate of approximately 2% (in fact, it's 1.94%). Any unexpected increase in the inflation rate would decrease the real interest rate. Banks and other lenders adjust for this inflation risk either by including an inflation risk premium to fixed interest rate loans, or lending at an adjustable rate.

## Positive

;Labour-market adjustments: Nominal wages are Sticky (economics), slow to adjust downwards. This can lead to prolonged disequilibrium and high unemployment in the labor market. Since inflation allows real wages to fall even if nominal wages are kept constant, moderate inflation enables labor markets to reach equilibrium faster. ;Room to maneuver: The primary tools for controlling the money supply are the ability to set the discount window, discount rate, the rate at which banks can borrow from the central bank, and open market operations, which are the central bank's interventions into the bonds market with the aim of affecting the nominal interest rate. If an economy finds itself in a recession with already low, or even zero, nominal interest rates, then the bank cannot cut these rates further (since negative nominal interest rates are impossible) to stimulate the economy this situation is known as a
liquidity trap A liquidity trap is a situation, described in Keynesian economics, in which, "after the rate of interest has fallen to a certain level, liquidity preference may become virtually absolute in the sense that almost everyone prefers holding cash ...
. ;Mundell–Tobin effect: The Nobel Memorial Prize in Economic Sciences, Nobel laureate Robert Mundell noted that moderate inflation would induce savers to substitute lending for some money holding as a means to finance future spending. That substitution would cause market clearing real interest rates to fall. The lower real rate of interest would induce more borrowing to finance investment. In a similar vein, Nobel laureate James Tobin noted that such inflation would cause businesses to substitute investment in physical capital (plant, equipment, and inventories) for money balances in their asset portfolios. That substitution would mean choosing the making of investments with lower rates of real return. (The rates of return are lower because the investments with higher rates of return were already being made before.) The two related effects are known as the Mundell–Tobin effect. Unless the economy is already overinvesting according to models of Economic growth, economic growth theory, that extra investment resulting from the effect would be seen as positive. ;Instability with deflation: Economist Sho-Chieh Tsiang, S.C. Tsiang noted that once substantial deflation is expected, two important effects will appear; both a result of money holding substituting for lending as a vehicle for saving. The first was that continually falling prices and the resulting incentive to hoard money will cause instability resulting from the likely increasing fear, while money hoards grow in value, that the value of those hoards are at risk, as people realize that a movement to trade those money hoards for real goods and assets will quickly drive those prices up. Any movement to spend those hoards "once started would become a tremendous avalanche, which could rampage for a long time before it would spend itself." Thus, a regime of long-term deflation is likely to be interrupted by periodic spikes of rapid inflation and consequent real economic disruptions. The second effect noted by Tsiang is that when savers have substituted money holding for lending on financial markets, the role of those markets in channeling savings into investment is undermined. With nominal interest rates driven to zero, or near zero, from the competition with a high return money asset, there would be no price mechanism in whatever is left of those markets. With financial markets effectively euthanized, the remaining goods and physical asset prices would move in perverse directions. For example, an increased desire to save could not push interest rates further down (and thereby stimulate investment) but would instead cause additional money hoarding, driving consumer prices further down and making investment in consumer goods production thereby less attractive. Moderate inflation, once its expectation is incorporated into nominal interest rates, would give those interest rates room to go both up and down in response to shifting investment opportunities, or savers' preferences, and thus allow financial markets to function in a more normal fashion.

## Cost-of-living allowance

The real purchasing power of fixed payments is eroded by inflation unless they are inflation-adjusted to keep their real values constant. In many countries, employment contracts, pension benefits, and government entitlements (such as social security) are tied to a cost-of-living index, typically to the
consumer price index#REDIRECT consumer price index A consumer price index measures changes in the price level of a weighted average market basket of Goods, consumer goods and Services marketing, services purchased by households. A CPI is a statistical estimate con ...
. A ''cost-of-living adjustment'' (COLA) adjusts salaries based on changes in a cost-of-living index. It does not control inflation, but rather seeks to mitigate the consequences of inflation for those on fixed incomes. Salaries are typically adjusted annually in low inflation economies. During hyperinflation they are adjusted more often. They may also be tied to a cost-of-living index that varies by geographic location if the employee moves. Annual escalation clauses in employment contracts can specify retroactive or future percentage increases in worker pay which are not tied to any index. These negotiated increases in pay are colloquially referred to as cost-of-living adjustments ("COLAs") or cost-of-living increases because of their similarity to increases tied to externally determined indexes.

# Controlling inflation

## Monetary policy

Although both fiscal policy, fiscal and monetary policy can affect inflation, ever since the 1980s, most countries primarily rely on monetary policy to control inflation. When inflation beyond an acceptable level is taking place, the country's
central bank A central bank, reserve bank, or monetary authority is an institution that manages the and of a or formal monetary union, and oversees their . In contrast to a , a central bank possesses a on increasing the . Most central banks also have ...

can increase the
interest rate An interest rate is the amount of interest In and , interest is payment from a or deposit-taking financial institution to a or depositor of an amount above repayment of the (that is, the amount borrowed), at a particular rate. It is disti ...
, which typically will tend to slow or stop the growth of the
money supply In macroeconomics, the money supply (or money stock) refers to the total volume of money held by the public at a particular point in time in an economy. There are several ways to define "money", but standard measures usually include Circulati ...
. Some central banks have a symmetrical inflation target while others only control inflation when it rises above a threshold, whether publicly disclosed or not. In the 21st century, most economists favor a low and steady rate of inflation. In most countries, central banks or other monetary authorities are tasked with keeping their interbank lending rates at low stable levels, and the target inflation rate of about 2% to 3%. Central banks target a low inflation rate because they believe that high inflation is economically costly because it would create uncertainty about differences in relative prices and about the inflation rate itself. A low positive inflation rate is targeted rather than a zero or negative one because the latter could cause or worsen recessions; low (as opposed to zero or Deflation, negative) inflation reduces the severity of economic recessions by enabling the labor market to adjust more quickly in a downturn, and reduces the risk that a
liquidity trap A liquidity trap is a situation, described in Keynesian economics, in which, "after the rate of interest has fallen to a certain level, liquidity preference may become virtually absolute in the sense that almost everyone prefers holding cash ...
prevents monetary policy from stabilizing the economy. Higher interest rates reduce the economy's money supply because fewer people seek loans. When banks make loans, the loan proceeds are generally deposited in bank accounts that are part of the money supply. Therefore, when a person pays back a loan and no other loans are made to replace it, the amount of bank deposits and hence the money supply decrease. For example, in the early 1980s, when the federal funds rate exceeded 15%, the quantity of Federal Reserve dollars fell 8.1%, from US$8.6 trillion down to$7.9 trillion. In the latter part of the 20th century, there was a debate between Keynesians and monetarists about the appropriate instrument to use to control inflation. Monetarists emphasize a low and steady growth rate of the money supply, while the Keynesians emphasize reducing aggregate demand during economic expansions and increasing demand during recessions to keep inflation stable. Control of aggregate demand can be achieved using both monetary policy and fiscal policy (increased taxation or reduced government spending to reduce demand).

## Other methods

### Fixed exchange rates

Under a fixed exchange rate currency regime, a country's currency is tied in value to another single currency or to a basket of other currencies (or sometimes to another measure of value, such as gold). A fixed exchange rate is usually used to stabilize the value of a currency, vis-a-vis the currency it is pegged to. It can also be used as a means to control inflation. However, as the value of the reference currency rises and falls, so does the currency pegged to it. This essentially means that the inflation rate in the fixed exchange rate country is determined by the inflation rate of the country the currency is pegged to. In addition, a fixed exchange rate prevents a government from using domestic monetary policy to achieve macroeconomic stability. Under the Bretton Woods system, Bretton Woods agreement, most countries around the world had currencies that were fixed to the U.S. dollar. This limited inflation in those countries, but also exposed them to the danger of speculative attacks. After the Bretton Woods agreement broke down in the early 1970s, countries gradually turned to floating exchange rates. However, in the later part of the 20th century, some countries reverted to a fixed exchange rate as part of an attempt to control inflation. This policy of using a fixed exchange rate to control inflation was used in many countries in South America in the later part of the 20th century (e.g. Argentine Currency Board, Argentina (1991–2002), Bolivia, Brazil, Chile, Pakistan, etc.).

### Gold standard

The gold standard is a monetary system in which a region's common medium of exchange is paper notes (or other monetary token) that are normally freely convertible into pre-set, fixed quantities of gold. The standard specifies how the gold backing would be implemented, including the amount of Bullion coin, specie per currency unit. The currency itself has no ''innate value'', but is accepted by traders because it can be redeemed for the equivalent specie. A Silver certificate (United States), U.S. silver certificate, for example, could be redeemed for an actual piece of silver. The gold standard was partially abandoned via the international adoption of the Bretton Woods system. Under this system all other major currencies were tied at fixed rates to the US dollar, which itself was tied by the US government to gold at the rate of US\$35 per ounce. The Bretton Woods system broke down in 1971, causing most countries to switch to fiat currency, fiat money money backed only by the laws of the country. Under a gold standard, the long term rate of inflation (or deflation) would be determined by the growth rate of the supply of gold relative to total output. Critics argue that this will cause arbitrary fluctuations in the inflation rate, and that monetary policy would essentially be determined by gold mining.

### Wage and price controls

Another method attempted in the past have been wage and price controls ("incomes policies"). Wage and price controls have been successful in wartime environments in combination with rationing. However, their use in other contexts is far more mixed. Notable failures of their use include Nixon shock, the 1972 imposition of wage and price controls by Richard Nixon. More successful examples include the The Accord, Prices and Incomes Accord in Australia and the Wassenaar Agreement in the Netherlands. In general, wage and price controls are regarded as a temporary and exceptional measure, only effective when coupled with policies designed to reduce the underlying causes of inflation during the Wage and price controls, wage and price control regime, for example, winning the war being fought. They often have perverse effects, due to the distorted signals they send to the market. Artificially low prices often cause rationing and shortages and discourage future investment, resulting in yet further shortages. The usual economic analysis is that any product or service that is under-priced is overconsumed. For example, if the official price of bread is too low, there will be too little bread at official prices, and too little investment in bread making by the market to satisfy future needs, thereby exacerbating the problem in the long term. Temporary controls may ''complement'' a recession as a way to fight inflation: the controls make the recession more efficient as a way to fight inflation (reducing the need to increase unemployment), while the recession prevents the kinds of distortions that controls cause when demand is high. However, in general the advice of economists is not to impose price controls but to liberalize prices by assuming that the economy will adjust and abandon unprofitable economic activity. The lower activity will place fewer demands on whatever commodities were driving inflation, whether labor or resources, and inflation will fall with total economic output. This often produces a severe recession, as productive capacity is reallocated and is thus often very unpopular with the people whose livelihoods are destroyed (see creative destruction).

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# References

* Measurement of inflation is discussed in Ch. 2, pp. 45–50; Money growth & Inflation in Ch. 7, pp. 266–269; Keynesian business cycles and inflation in Ch. 9, pp. 308–348. * * * Measurement of inflation is discussed in Ch. 2, pp. 22–32; Money growth & Inflation in Ch. 4, pp. 81–107; Keynesian business cycles and inflation in Ch. 9, pp. 238–255. * *

* World Bank, 2018
''Inflation in Emerging and Developing Economies: Evolution, Drivers and Policies''
Edited by Jongrim Ha, M. Ayhan Kose, and Franziska Ohnsorge. * Leonardo Auernheimer, Auernheimer, Leonardo, "The Honest Government's Guide to the Revenue From the Creation of Money," Journal of Political Economy, Vol. 82, No. 3, May/June 1974, pp. 598–606. * William Baumol, Baumol, William J. and Alan S. Blinder, ''Macroeconomics: Principles and Policy'', Tenth edition. Thomson South-Western, 2006. * Milton Friedman, Friedman, Milton, Nobel lecture
Inflation and unemployment
1977 * Frederic Mishkin, Mishkin, Frederic S., ''The Economics of Money, Banking, and Financial Markets'', New York, Harper Collins, 1995. * Federal Reserve Bank of Boston
"Understanding Inflation and the Implications for Monetary Policy: A Phillips Curve Retrospective"
Conference Series 53, June 9–11, 2008, Chatham, Massachusetts. (Also cf. Phillips curve article)

OECD Consumer Price Index

United States Bureau of Labor Statistics – Consumer Price Index

General purpose compounded inflation calculator

U.S. Cost of Living Calculator (1913–present)
(American Institute for Economic Research, AIER)
U.S. Inflation Calculator (1913–present)
(US Bureau of Labor Statistics, US BLS)
U.S. Inflation (historical documents)
(Federal Reserve Economic Data#Other Federal Reserve Bank of St. Louis data services, FRASER)
World Inflation (1290–2006)
(
Consumer Price Index#REDIRECT consumer price index A consumer price index measures changes in the price level of a weighted average market basket of Goods, consumer goods and Services marketing, services purchased by households. A CPI is a statistical estimate con ...
) (Swedish Riksbank)
World Bank annual inflation rates for all countries

Inflation : Definition, WPI, CPI, Measurement and Causes
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