We examined the interrater reliability and diagnostic efficiency of clinician report (both the treating clinician and independent expert clinical interviewer) and patient self-report of clinically meaningful information pertaining to adaptive functioning. A convenience sample of clinicians (N = 80) and patients (N = 170) from eight community mental health clinics in Israel participated in the study. Our findings suggest that clinicians overall reliably report on adaptive functioning of patients (overall correct classification rates range, 0.74–0.98). Yet, in some areas, they may fail to collect necessary information such as self-mutilation history, loss of job in the past 5 years, and adult physical abuse. The patterns of higher versus lower diagnostic efficiency suggest that both treating clinicians and independent clinician interviewers tend to make judgments conservatively, essentially sacrificing sensitivity for specificity, not diagnosing events unless they were certain, thus maximizing false-negatives and minimizing false-positives.