Читать книгу Abnormal Psychology - William J. Ray - Страница 163

Concerns about the accuracy of assessment and classification of psychopathology require us to consider two very different questions. The first has to do with the person who is being interviewed. We need to know if the person is giving us information that is accurate or not. Sometimes, individuals will “fake bad” if there is some advantage such as receiving a larger disability payout. Other times, individuals will “fake good” and deny there are any problems.

The second question is which assessment instruments to use. An assessment instrument can be an interview, an inventory, a mood scale, and so forth. In considering instruments, we think about measurement. Measurement considerations help to define the variety of instruments that we use and the theoretical variables that these reflect.

Traditionally, the two key measurement issues are reliability and validity. That is, does an instrument measure the construct consistently (reliability) and accurately (validity)? The measurement of temperature, for example, is based on the kinetic theory of heat, which helped define the type of devices used. With psychopathology, however, we lack exact formal definitions that tell us exactly how to make measurements. In fact, we are both trying to learn about disorders and creating techniques for making diagnoses. This makes reliability and validity considerations both more difficult and more important.

reliability: consistency of the measurement by an assessment instrument