Assessing the reliability of Beck Depression Inventory scores: Reliabilitygeneralization across studies

The reliability estimates for the Beck Depression Inventory (BDI) scores ac ross studies were accumulated and summarized in a meta-analysis. Only 7.5% of the articles reviewed reported meaningful reliability estimates, indicat ing that the logic of "test score reliability" generally has not prevailed in clinical psychology regarding application of BDI. Analyses revealed that for BDI, the measurement error due to time sampling as captured by test-re test reliability estimate is considerably larger than the measurement error due to item heterogeneity and content sampling as captured by internal con sistency reliability estimate. Also, reliability estimates involving substa nce addicts were consistently lower than reliability estimates involving no rmal subjects, possibly due to restriction of range problems. Correlation a nalyses revealed that standard errors of measurement (SEMs) were not correl ated with reliability estimates but were substantially related to standard deviations of BDI scores, suggesting that SEMs should be considered in addi tion to reliability estimates when interpreting individual BDI scores.