Individual Choice and Sources of Error

Idiographic Evaluation of Psychosocial Rehabilitation

Abstract

This article briefly examines experimental approaches and sources of error in the evaluation of psychiatric or psychosocial rehabilitation programs: pre-post quasi-experimental designs, the selection of groups that are extreme on criterion measures, the problem of self-selection and differential attrition, the absence of no-treatment controls and nonblind assessment, and individual variation in response to poorly defined treatments. These factors become more problematic in evaluating ecologically based treatment that involves measuring individual progress to self-identified goals in individually selected environments. The psychosocial rehabilitation focus on individuals functioning in their natural environments has not yet met with an equally ecologically valid research methodology. This article describes an idiographic evaluation approach that characterizes individual responses to treatment and that combines small group methodology using the group as its own control to provide a practically attainable assessment of treatment effectiveness in applied rehabilitation settings.