A meta-analysis of the reliability and validity of the Rorschach

The results of a meta-analysis of Rorschach studies indicate that reliabilities in the order of .83 and higher and validity coefficients of .45 or .50 and higher can be expected for the Rorschach--when hypotheses supported by empirical or theoretical rationales are tested using reasonably powerful statistics. Three important determinants of variance accounted for in a variety of Rorschach scores were identified in 530 statistics from 39 papers published in the Journal of Personality Assessment from 1971 to 1980. The a priori theoretical or empirical evidence determining the likelihood of obtaining significant results, and the power of the statistic used to measure the results, as well as the interaction between the likelihood of results and the power of the statistic used, were all significant determinants of the proportion of variance accounted for in the Rorschach measures reported.