The Hamilton Rating Scale for Depression: A meta-analytic reliability generalization study

Reliability generalization is a meta-analytic approach to study how reliability estimates of a test scores depend on the specific characteristics under which the test is applied and, as a consequence, the risks of inducing score reliability from previous applications of the test. The Hamilton Rating Scale for Depression (HAMD) is one the most popular measurement instruments in clinical psychology to assess depressive symptoms and several versions of the scale have been designed. The present meta-analytic study provided a reliability generalization (RG) study of the HAM-D scale for estimating the typical measurement reliability, to test the heterogeneity of reliability estimates across studies, to examine the influence of study characteristics and to compare the results with those obtained in previous RG studies on other depression scales. Analyses carried out with 35 alpha coefficients, obtained from 23 published research studies, showed a mean reliability of 79 (SD = 14), high heterogeneity across studies and several study characteristics related to score reliability, mainly the number of items, the variability of the test scores and the type of disorder studied in the sample. Implications for researchers and clinicians using the HAM-D scale are discussed.