Rosenthal, Robert. 1980. "Comparing Within- and Between-Subjects Studies." SOCIOLOGICAL METHODS & RESEARCH 9, no. 1: 127-136.
Studies employing within-subjects designs may be compared with those employing between-subjects designs in a variety of ways. We discuss and illustrate the comparisons of variabilities, including within-condition variances and precisions as well as the comparisons of means and of mean differences. Our discussion emphasizes the importance of trying to understand the sources of differences.