Intraclass Correlation

The words intraclass correlation (ICC) refer to a set of coefficients representing the relationship between variables of the same class. Variables of the same class share a common metric and variance, which generally means that they measure the same thing. Examples include twin studies and two or more raters evaluating the same targets. ICCs are used frequently to assess the reliability of raters. The Pearson correlation coefficient usually relates measures of different classes, such as height [Page 637]and weight or stress and depression, and is an interclass correlation.

Table 1 Data on Sociability of Dyads of Gay Couples

Most articles on ICC focus on the computation of different ICCs and their tests and confidence limits. This entry focuses more on the uses of several different ICCs.

The different ...