In
statistics, a unit of observation is the unit described by the
data
In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpret ...
that one analyzes. A study may treat groups as a unit of observation with a country as the unit of analysis, drawing conclusions on group characteristics from data collected at the national level. For example, in a study of the
demand for money, the unit of observation might be chosen as the individual, with different observations (data points) for a given point in time differing as to which individual they refer to; or the unit of observation might be the country, with different observations differing only in regard to the country they refer to.
Unit of observation vs unit of analysis
The unit of observation should not be confused with the
unit of analysis
The unit of analysis is the entity that frames what is being looked at in a study, or is the entity being studied as a whole. In social science research, at the macro level, the most commonly referenced unit of analysis, considered to be a society ...
. A study may have a differing unit of observation and unit of analysis: for example, in
community
A community is a social unit (a group of living things) with commonality such as place, norms, religion, values, customs, or identity. Communities may share a sense of place situated in a given geographical area (e.g. a country, villag ...
research, the
research design may collect data at the individual level of observation but the
level of analysis might be at the neighborhood level, drawing conclusions on neighborhood characteristics from data collected from individuals. Together, the unit of observation and the
level of analysis define the
population
Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using ...
of a research enterprise.
Data point
A data point or observation is a set of one or more
measurements on a single member of the unit of observation. For example, in a study of the determinants of
money demand with the unit of observation being the individual, a data point might be the values of income, wealth, age of individual, and number of dependents.
Statistical inference about the population would be conducted using a
statistical sample
In statistics, quality assurance, and survey methodology, sampling is the selection of a subset (a statistical sample) of individuals from within a statistical population to estimate characteristics of the whole population. Statisticians attempt ...
consisting of various such data points.
In addition, in
statistical graphics
Statistical graphics, also known as statistical graphical techniques, are graphics used in the field of statistics for data visualization.
Overview
Whereas statistics and data analysis procedures generally yield their output in numeric or ta ...
, a "data point" may be an individual item with a statistical display; such points may relate to either a single member of a population or to a
summary statistic calculated for a given subpopulation.
Types of data
The measurements contained in a unit of observation are formally ''typed'', where here ''type'' is used in a way compatible with
datatype
In computer science and computer programming, a data type (or simply type) is a set of possible values and a set of allowed operations on it. A data type tells the compiler or interpreter how the programmer intends to use the data. Most progra ...
in
computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, ...
; so that the type of measurement can specify whether the measurement results in a
Boolean
Any kind of logic, function, expression, or theory based on the work of George Boole is considered Boolean.
Related to this, "Boolean" may refer to:
* Boolean data type, a form of data with only two possible values (usually "true" and "false" ...
value from , an
integer
An integer is the number zero (), a positive natural number (, , , etc.) or a negative integer with a minus sign ( −1, −2, −3, etc.). The negative numbers are the additive inverses of the corresponding positive numbers. In the language ...
or
real number
In mathematics, a real number is a number that can be used to measurement, measure a ''continuous'' one-dimensional quantity such as a distance, time, duration or temperature. Here, ''continuous'' means that values can have arbitrarily small var ...
, the identity of some
category
Category, plural categories, may refer to:
Philosophy and general uses
*Categorization, categories in cognitive science, information science and generally
* Category of being
* ''Categories'' (Aristotle)
* Category (Kant)
* Categories (Peirce) ...
, or some
vector
Vector most often refers to:
*Euclidean vector, a quantity with a magnitude and a direction
*Vector (epidemiology), an agent that carries and transmits an infectious pathogen into another living organism
Vector may also refer to:
Mathematic ...
or
array
An array is a systematic arrangement of similar objects, usually in rows and columns.
Things called an array include:
{{TOC right
Music
* In twelve-tone and serial composition, the presentation of simultaneous twelve-tone sets such that the ...
.
The implication of ''point'' is often that the data may be plotted in a graphic display, but in many cases the data are
processed numerically before that is done. In the context of
statistical graphics
Statistical graphics, also known as statistical graphical techniques, are graphics used in the field of statistics for data visualization.
Overview
Whereas statistics and data analysis procedures generally yield their output in numeric or ta ...
, measured values for individuals or summary statistics for different subpopulations are displayed as separate symbols within a display; since such symbols can differ by shape, size and colour, a single ''data point'' within a display can convey multiple aspects of the set of measurements for an individual or subpopulation.
See also
*
Data
In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpret ...
*
Data collection system Data collection system (DCS) is a computer application that facilitates the process of data collection, allowing specific, structured information to be gathered in a systematic fashion, subsequently enabling data analysis to be performed on the inf ...
*
Observation error
*
Sample point
References
{{DEFAULTSORT:Unit Of Observation
Statistical data types
Social research