Correcting for Multiple Comparisons in Studies of Dream Content: A Statistical Addition to the Hall/Van de Castle Coding System

This article addresses the issue of potential false positives when multiple tests are carried out in comparing 2 samples with the content indicators used in the Hall and Van de Castle (1966) coding system for dream content. Using an algorithm based on the Benjamini-Hochberg (Benjamini & Hochberg, 1995) correction for the False Discovery Rate, it first compares findings for men and women in a large normative sample; all 12 of the statistically significant differences at the.05 level remain, along with 10 of 11 below .01. The article then compares results from an individual's dream series with the norms for women; 10 of the 12 significant p values at the.05 level remain, along with 4 of 5 below .01. The article concludes that earlier findings with the Hall-Van de Castle system can be viewed as established findings, and recommends that the correction formula be used with large samples.