Covariate

Covariate

In statistics, a covariate is a variable that is possibly predictive of the outcome under study. A covariate may be of direct interest or it may be a confounding or interacting variable.

The alternative terms explanatory variable, independent variable, or predictor, are used in a regression analysis. In econometrics, the term "control variable" is usually used instead of "covariate". In a more specific usage, a covariate is a secondary variable that can affect the relationship between the dependent variable and other independent variables of primary interest.

An example is provided by the analysis of trend in sea-level by Woodworth (1987). Here the dependent variable (and variable of most interest) was the annual mean sea level at a given location for which a series of yearly values were available. The primary independent variable was "time". Use was made of a "covariate" consisting of yearly values of annual mean atmospheric pressure at sea level. The results showed that inclusion of the covariate allowed improved estimates of the trend against time to be obtained, compared to analyses which omitted the covariate.

See also

References

  • A Dictionary of Epidemiology: Fourth Edition. John M Last ed. Oxford UP 2001.
  • The Cambridge Dictionary of Statistics (2nd Edition). B.S.Everitt , Cambridge UP 2002.
  • Woodworth, P.L. (1987) Trends in U.K. mean sea level. Marine Geodesy, 11, 57-87.

Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • covariate — noun Date: 1965 any of two or more random variables exhibiting correlated variation …   New Collegiate Dictionary

  • covariate — noun A variable that is possibly predictive of the outcome under study. See Also: covary, covariance …   Wiktionary

  • covariate — co·va·ri·ate (ko varґe ət) a variable that is related to a second variable …   Medical dictionary

  • covariate — co·variate …   English syllables

  • covariate — ¦kōˌ noun Etymology: co + variate (II) : any of two or more random variables exhibiting correlated variation …   Useful english dictionary

  • Time-varying covariate — A time varying covariate is a term used in statistics, particularly in survival analyses. It reflects the phenomenon that a covariate is not necessarily fixed. For instance, if one wishes to examine the link between area of residence and cancer,… …   Wikipedia

  • Linear regression — Example of simple linear regression, which has one independent variable In statistics, linear regression is an approach to modeling the relationship between a scalar variable y and one or more explanatory variables denoted X. The case of one… …   Wikipedia

  • Analysis of covariance — (ANCOVA) is a general linear model with one continuous outcome variable and one or more factors. ANCOVA is a merger of ANOVA and regression for continuous variables. ANCOVA tests whether certain factors have an effect on the outcome variable… …   Wikipedia

  • 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. In a proportional hazards model, the unique effect of a unit… …   Wikipedia

  • Experiment — Experimental redirects here. For the musical classification, see Experimental music. For other uses, see Experiment (disambiguation). Even very young children perform rudimentary experiments in order to learn about the world. An experiment is a… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”