American Psychological Association

This article summarizes evidence and issues associated with psychological assessment. Data from more than 125 meta-analyses on test validity and 800 samples examining multimethod assessment suggest 4 general conclusions: (a) Psychological test validity is strong and compelling, (b) psychological test validity, is comparable to medical test validity, (c) distinct assessment methods provide unique sources of information, and (d) clinicians who rely exclu-sively on interviews are prone to incomplete understand-ings. Following principles for optimal nomothetic re-search, the authors suggest that a multimethod assessment battery provides a structured means for skilled clinicians to maximize the validity of individualized assessments. Future investigations should move beyond an examination of test scales to focus more on the role of psychologists who use tests as helpful tools to furnish patients and referral sources with professional consultation. F or clinical psychologists, assessment is second onlyto psychotherapy in terms of its professional im-portance (Greenberg, Smith, & Muenzen, 1995; Norcross, Karg, & Prochaska, 1997; Phelps, Eisman, & Kohout, 1998). However, unlike psychotherapy, formal assessment is a distinctive and unique aspect of psycholog-ical practice relative to the activities performed by other health care providers. Unfortunately, with dramatic health care changes over the past decade, the utility of psycho-logical assessment has been increasingly challenged (Eis-man et al., 1998, 2000), and there has been declining use of the time-intensive, clinician-administered instruments that have historically defined professional practice (Piotrowski