The %INTRACC macro calculates reliabilities for intraclass correlations. The macro calculates the six intraclass correlations discussed in Shrout and Fleiss (1979). Additionally it calculates two intraclass correlations using formulae from Winer (1971) which are identical to two of the six from Shrout and Fleiss. It also calculates the reliability of the mean of nrater ratings, where nrater is a parameter of the macro, using the Spearmen-Brown prophecy formula so that one can examine the effect obtaining more raters would have on the reliability of a mean.