The lists have adequate internal consistency; the close agreement between the alternative forms is a strong feature (13, p273). Evidence for the stability of the measurement, however, is sparse and the available retest results are low. At present, they are limited to the state form; data on the reliability of the trait forms are needed (9).
Commentaries on the validity of the DACL give conflicting impressions. This seems to reflect reviewers’ differing expectations of the method and their different reactions to its comparatively narrow scope. Lubin intentionally focused on mood, a major, but not the sole, symptom of depression. The DACL do not include DSM criteria such as the inability to think or concentrate, thoughts of suicide, changes in appetite, sleep, or psychomotor activity, and other behavioral manifestations (13, p286; 28, p421). Reflecting this focus, concurrent validity is moderate: correlations with psychiatric ratings of depression are somewhat lower than those of other self-rating instruments. Correlations between the DACL and other self-report depression measures are low to moderate (21); the low correlations between the DACL and the somatic items in the Zung and Beck instruments are to be expected (1, Tables 23–24). Although the check lists can be used to screen for depression, they must not be viewed as diagnostic. Lubin has, however, developed a brief Depression Extender Check List (DECL), which samples additional aspects of depression to form a diagnostic instrument (B. Lubin, personal communication, 1992).