Abstract
There is evidence that the quality of controlled clinical trials affects the results that are obtained. A systematic approach to the assessment of quality is required for psychiatric research. This study set out to develop an instrument for the assessment of the quality of controlled trials of interventions for depressive and non‐psychotic conditions. A pilot study led to the development of a scale containing 23 items covering a wide range of aspects of quality including objective formulation, design, presentation of results, analysis and quality of conclusions. Scoring criteria were devised and the scale was then subjected to reliability testing using a random sample of trials of treatment for depression and ‘neurosis’. The scale showed moderate inter‐rater reliability and results were comparable to those obtained with shorter instruments. It was quick and easy to use. There were significant correlations between year of publication and overall quality score with later studies showing higher quality. The instrument developed here provides a systematic approach to the assessment of quality for use in critical appraisal of individual studies and meta‐analysis. However, the scoring process should be used cautiously since inter‐rater agreement was only moderate. Copyright © 2001 Whurr Publishers Ltd.