The Diagnostic Knowledge Inventory: a measure of knowledge about psychiatric diagnosis

A psychometrically sound measure of knowledge of psychiatric disorders and diagnoses (consistent with both DSM-III and DSM-III-R) was constructed for use by mental health and health care professionals. No such measure otherwise exists, in spite of its potential value as an educational tool and in research on clinical diagnosis. The diagnostic accuracy (content validity) of a large item pool of brief case vignettes was verified in a prestudy by a team of experts. This item pool then was reduced by half, and two forms of the measure were constructed based on an item analysis that used a heterogeneous sample of clinically trained and untrained respondents (Study 1). Reliability and validity were demonstrated using a cross-validation sample (Study 2). Finally, comparisons were made between practicing mental health professionals and controls; these supported the measure's validity (Study 3). Overall, the measure demonstrated concurrent validity (by distinguishing clinically trained from untrained respondents) and reliability (by showing internal consistency and inter-form association). Potential uses of the measure in research and training concerned with clinical diagnosis are discussed.