# correlation

1. (noun) In statistical analysis, a broad term describing how a change in one variable is associated with a similar pattern of variation in another variable across cases in a dataset.

2. (noun) A normalized indicator of covariance.

Example: In infants, shoe size is positively correlated with the number of teeth

Audio Pronunciation: (cor·re·la·tion)

Usage Notes:

• Plural: correlations
• A correlation can be positive or negative. When variables move in the same direction they are positively correlated and when an increase in one variable, decreases another variable they are negatively correlated.
• Perfect correlation is unlikely in the social sciences.
• Correlation does not always equal causation. Inappropriate inference of causality is referred to as a spurious relationship (not to be confused with spurious correlation). Correlation only reveals a relationship between variables but not the context; the presence of a third factor that accounts for the association between variables is a confounding variable. Researchers must employ a rigorous methodology in order to adequately infer the nature and direction of correlated variables. For example, the positive correlation between hat sales and ice cream sales is likely not because the wearing of hats promotes a craving for ice cream but because of a third, confounding variable: hot weather.
• Correlation between two variables is measured statistically by a correlation coefficient (coefficient of association). There are different tests of correlation depending on the type of data and the characteristic of relationship being examined. A common test is the Pearson product-movement correlation (commonly referred to as Pearson correlation, r) which tests the linear correlation between two variables where data approximates interval level characteristics. When data does not meet the assumptions for the Pearson correlation test, nonparametric tests for rank correlation may be applied.
• Types:
• Also called correlativity.
• When two variables (verb) correlate they are (adverb) correlationally or (adverb) correlatively connected and (adjective) correlational or (adjective) correlative and (adjective) correlational analysis determines the strength of two variables using (n). correlational statistics.