As is true of people in general, the human traits of disabled population tend to be more or less normally distributed, and individual differences are marked. This chapter discusses issues relating to psychosocial / vocational (PSV) evaluation in particular and the psychological aspects of evaluative processes in general. Three approaches to evaluation are: interviewing, psychometric testing, and situational or functional assessment. Rehabilitation services typically aim to help a person make choices/changes in life after disability. Years ago, people with serious disabilities might spend months on an inpatient rehabilitation unit, and the usual treatment protocol allowed for substantial psychological and vocational services. Although the practice of evaluation in rehabilitation has changed substantially, it continues to have many important functions, including: prediction of behavior, understanding the individual and his or her support system, assessment of functional capacities, service planning, clinical decision making, assessment of progress and outcomes, screening, adjudication and research.