Medical statistics (also health statistics) deals with applications of

statistics Statistics (from German language, German: ', "description of a State (polity), state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a s ...

medicine Medicine is the science and Praxis (process), practice of caring for patients, managing the Medical diagnosis, diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, ...

and the

health science The following outline is provided as an overview of and topical guide to health sciences: Health sciences – those sciences that focus on health, or health care, as core parts of their subject matter. Health sciences relate to multiple ...

s, including

epidemiology Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and Risk factor (epidemiology), determinants of health and disease conditions in a defined population, and application of this knowledge to prevent dise ...

public health Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the de ...

forensic medicine Forensic medicine is a broad term used to describe a group of medical specialties which deal with the examination and diagnosis of individuals who have been injured by or who have died because of external or unnatural causes such as poisoning, assa ...

, and

clinical research Clinical research is a branch of medical research that involves people and aims to determine the effectiveness (efficacy) and safety of medications, devices, diagnostic products, and treatment regimens intended for improving human health. The ...

. Medical statistics has been a recognized branch of statistics in the United Kingdom for more than 40 years, but the term has not come into general use in North America, where the wider term '

biostatistics Biostatistics (also known as biometry) is a branch of statistics that applies statistical methods to a wide range of topics in biology. It encompasses the design of biological experiments, the collection and analysis of data from those experimen ...

' is more commonly used.Dodge, Y. (2003) ''The Oxford Dictionary of Statistical Terms'', OUP. However, "biostatistics" more commonly connotes all applications of statistics to

biology Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and ...

. Medical statistics is a subdiscipline of statistics.

It is the science of summarizing, collecting, presenting and interpreting data in medical practice, and using them to estimate the magnitude of associations and test hypotheses. It has a central role in medical investigations. It not only provides a way of organizing information on a wider and more formal basis than relying on the exchange of anecdotes and personal experience, but also takes into account the intrinsic variation inherent in most biological processes.

Use in medical hypothesis testing

In medical hypothesis testing, the medical research is often evaluated by means of the confidence interval, the P value, or both.

Confidence interval

Frequently reported in medical research studies is the confidence interval (CI), which indicates the consistency and variability of the medical results of repeated medical trials. In other words, the confidence interval shows the range of values where the expected true estimate would exist within this specific range, if the study was performed many times. Most biomedical research is not able to use a total population for a study. Instead, samples of the total population are what are often used for a study. From the sample, inferences can be made of the total population by means of a sample statistic and the estimation of error, presented as a range of values.

P value

Frequently used in medical studies is the statistical significance of P < 0.05. The P value is the probability of no effect or no difference (

null hypothesis The null hypothesis (often denoted ''H''0) is the claim in scientific research that the effect being studied does not exist. The null hypothesis can also be described as the hypothesis in which no relationship exists between two sets of data o ...

) of obtaining a result essentially equal to what was actually observed. The P stands for probability and measures how likely it is that any observed difference between groups is due to chance. The P value function between 0 and 1. The closer to 0, the less likely the results are due to chance. The closer to 1, the higher the probability that the results are actually due to chance.

Pharmaceutical statistics

Pharmaceutical statistics is the application of statistics to matters concerning the

pharmaceutical industry The pharmaceutical industry is a medical industry that discovers, develops, produces, and markets pharmaceutical goods such as medications and medical devices. Medications are then administered to (or self-administered by) patients for curing ...

. This can be from issues of

design of experiments The design of experiments (DOE), also known as experiment design or experimental design, is the design of any task that aims to describe and explain the variation of information under conditions that are hypothesized to reflect the variation. ...

, to analysis of drug trials, to issues of commercialization of a medicine. There are many professional bodies concerned with this field including: * European Federation of Statisticians in the Pharmaceutical Industry * Statisticians In The Pharmaceutical Industry

Clinical biostatistics

Clinical biostatistics is concerned with research into the principles and methodology used in the design and analysis of

and to apply

statistical theory The theory of statistics provides a basis for the whole range of techniques, in both study design and data analysis, that are used within applications of statistics. The theory covers approaches to statistical-decision problems and to statistica ...

clinical medicine Medicine is the science and Praxis (process), practice of caring for patients, managing the Medical diagnosis, diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, ...

. Clinical biostatistics is taught in

postgraduate Postgraduate education, graduate education, or graduate school consists of academic or professional degrees, certificates, diplomas, or other qualifications usually pursued by post-secondary students who have earned an undergraduate (bachelor' ...

biostatistical and applied statistical degrees, for example as part of the BCA Master of Biostatistics program in Australia.

Basic concepts

;For describing situations *

Incidence (epidemiology) In epidemiology Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and Risk factor (epidemiology), determinants of health and disease conditions in a defined population, and application of this knowl ...

vs.

Prevalence In epidemiology, prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seatbelt use) at a specific time. It is derived by comparing the number o ...

vs.

Cumulative incidence In epidemiology, incidence reflects the number of new cases of a given medical condition in a population within a specified period of time. Incidence proportion Incidence proportion (IP), also known as cumulative incidence, is defined as the p ...

* Many

medical test A medical test is a medical procedure performed to detect, diagnose, or monitor diseases, disease processes, susceptibility, or to determine a course of treatment. Medical tests such as, physical and visual exams, diagnostic imaging, genetic ...

s (such as

pregnancy test A pregnancy test is used to determine whether a person is Pregnancy, pregnant or not. The two primary methods are testing for the pregnancy hormone (human chorionic gonadotropin (hCG)) in blood or urine using a pregnancy test kit, and scanning ...

s) have two possible results: positive or negative. However, tests will sometimes yield incorrect results in the form of false positives or false negatives. False positives and false negatives can be described by the statistical concepts of

type I and type II errors Type I error, or a false positive, is the erroneous rejection of a true null hypothesis in statistical hypothesis testing. A type II error, or a false negative, is the erroneous failure in bringing about appropriate rejection of a false null hy ...

, respectively, where the

is that the patient will test negative. The precision of a medical test is usually calculated in the form of positive predictive values (PPVs) and negative predicted values (NPVs). PPVs and NPVs of medical tests depend on intrinsic properties of the test as well as the

prevalence In epidemiology, prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seatbelt use) at a specific time. It is derived by comparing the number o ...

of the condition being tested for. For example, if any pregnancy test was administered to a population of individuals who were biologically incapable of becoming pregnant, then the test's PPV will be 0% and its NPV will be 100% simply because true positives and false negatives cannot exist in this population. *

Mortality rate Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular Statistical population, population, scaled to the size of that population, per unit of time. Mortality rate is typically ...

vs.

standardized mortality ratio In epidemiology, the standardized mortality ratio or SMR, is a quantity, expressed as either a ratio or percentage quantifying the increase or decrease in mortality of a study cohort with respect to the general population. Standardized mortality ...

vs. age-standardized mortality rate *

Pandemic A pandemic ( ) is an epidemic of an infectious disease that has a sudden increase in cases and spreads across a large region, for instance multiple continents or worldwide, affecting a substantial number of individuals. Widespread endemic (epi ...

vs.

epidemic An epidemic (from Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of hosts in a given population within a short period of time. For example, in meningococcal infection ...

vs.

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

vs.

syndemic Syndemics is the evaluation of how social and health conditions arise, in what ways they interact, and what upstream drivers may produce their interactions. The word is a blend of "synergy" and "epidemics". The idea of syndemics is that no disea ...

Serial interval The serial interval in the epidemiology of communicable (infectious) diseases is the time between successive cases in a chain of transmission. The serial interval is generally estimated from the interval between clinical onsets (if observable), in ...

vs.

incubation period Incubation period (also known as the latent period or latency period) is the time elapsed between exposure to a pathogenic organism, a chemical, or ionizing radiation, radiation, and when symptoms and signs are first apparent. In a typical infect ...

Cancer cluster A cancer cluster is a disease cluster in which a high number of cancer cases occurs in a group of people in a particular geographic area over a limited period of time. Historical examples of work-related cancer clusters are well documented in th ...

* Sexual network * Years of potential life lost *

Maternal mortality rate Maternal death or maternal mortality is defined in slightly different ways by several different health organizations. The World Health Organization (WHO) defines maternal death as the death of a pregnant mother due to complications related to p ...

* Perinatal mortality rate * Low birth weight ratio ;For assessing the effectiveness of an intervention: *

Absolute risk reduction The risk difference (RD), excess risk, or attributable risk is the difference between the risk of an outcome in the exposed group and the unexposed group. It is computed as I_e - I_u, where I_e is the incidence in the exposed group, and I_u is t ...

* Control event rate * Experimental event rate *

Number needed to harm In medicine, the number needed to harm (NNH) is an epidemiology, epidemiological measure that indicates how many persons on average need to be exposed to a risk-factor, risk factor over a specific period to cause harm in an average of one person ...

Number needed to treat The number needed to treat (NNT) or number needed to treat for an additional beneficial outcome (NNTB) is an epidemiology, epidemiological measure used in communicating the effectiveness of a health-care intervention, typically a treatment with me ...

Odds ratio An odds ratio (OR) is a statistic that quantifies the strength of the association between two events, A and B. The odds ratio is defined as the ratio of the odds of event A taking place in the presence of B, and the odds of A in the absence of B ...

Relative risk reduction In epidemiology, the relative risk reduction (RRR) or efficacy is the relative decrease in the risk In simple terms, risk is the possibility of something bad happening. Risk involves uncertainty about the effects/implications of an activity wit ...

Relative risk The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Together with risk difference and odds ratio, relative risk measures the association bet ...

Relative survival Relative survival of a disease, in survival analysis, is calculated by dividing the overall survival after diagnosis by the survival as observed in a similar population not diagnosed with that disease. A similar population is composed of individual ...

* Minimal clinically important difference

Related statistical theory

Survival analysis Survival analysis is a branch of statistics for analyzing the expected duration of time until one event occurs, such as death in biological organisms and failure in mechanical systems. This topic is called reliability theory, reliability analysis ...

Proportional hazards models Proportional hazards models are a class of survival models in statistics. Survival models relate the time that passes, before some event occurs, to one or more covariates that may be associated with that quantity of time. In a proportional haz ...

* Active control trials: clinical trials in which a kind of new treatment is compared with some other active agent rather than a placebo. * ADLS(Activities of daily living scale): a scale designed to measure physical ability/disability that is used in investigations of a variety of chronic disabling conditions, such as arthritis. This scale is based on scoring responses to questions about self-care, grooming, etc. * Actuarial statistics: the statistics used by actuaries to calculate liabilities, evaluate risks and plan the financial course of insurance, pensions, etc.

References

External links

Health-EU Portal
EU health statistics {{DEFAULTSORT:Medical Statistics Biostatistics Medical specialties Applied statistics Pharmaceutical statistics Clinical research