Personality Assessment: some facts

To most people-including many psychologists-psychological assessment is synonymous with testing. Experienced assessors, however, see a significant distinction between the two terms: assessment and testing. Testing refers to the use of a standardized instrument to obtain a specific interpretation about a person. In this way, it can be seen as analogous to medical tests, in which a laboratory analyzes a sample of urine or blood and obtains a value that has a more or less invariant meaning (e.g., a blood glucose level above 100 means the person is at risk for Type 2 Diabetes). The Hamilton Depression Scale, a self-report instrument that is often used by psychiatrists who treat depression, is an example of this.

Assessment, on the other hand, involves the use of psychological tests, but as a part of an integrated evaluation of multiple data sources (e.g., interviews, school records, observer ratings, etc.). The interpretation of the tests themselves is frequently contextual; that is a particular test finding might have a different meaning depending upon the circumstances of the individual's life. To give a simple example, an elevated depression scale on the MMPI-2 (Minnesota Multiphasic Personality Inventory-2), a commonly used personality inventory, would be interpreted differently for an individual who recently lost a spouse than for someone with no history of recent trauma. Comprehensive personality assessment requires a sophisticated set of skills, including familiarity with the administration and interpretation of many different tests, interviewing, clinical intuition, empathy, and the ability to integrate data from multiple different sources into a coherent whole. For this reason, the American Psychological Association recently declared personality assessment to be a specific proficiency in psychology, i.e., a unique set of skills that requires specific training.

So, why do we bother? After all, if this is a labor-intensive, highly specialized activity, is it really necessary? The short answer is yes. Clinicians-and others who are charged with evaluating individual - frequently make errors in judgment when relying upon a single source of information. In the context of mental health treatment, a competent personality assessment can:

• improve treatment efficiency by quantifying key aspects of patient functioning that then become the target of treatment
• identify intentional or unintentional response styles in which patients systematically underreport or overstate their symptoms and difficulties, and
• identify treatment-related information about patients that they may be unable or unwilling to communicate directly.

As a result, efficient use of assessment can lead to cost containment by minimizing diagnostic errors, identifying patient strengths that may be utilized in treatment, or conversely alerting clinicians to hidden impediments to effective treatment, and by providing patients with information that may enable them to make changes that obviate the need for further professional intervention. 

In subsequent posts, I will be discussing some of the specifics about assessment as well as some of the arenas outside of mental health treatment in which it can be important.