Psychometric evaluation of the outcome based performance measures.

The Outcome Based Performance Measures are widely used to evaluate and accredit organizations providing services to persons with disabilities. This study evaluated the interrater reliability, levels of difficulty for items, and factor groupings of this measure with 448 Nevadans with mental retardation. Results supported the measure's reliability and most of the items' levels of difficulty. Factor analysis yielded seven factors with item loadings that varied moderately from prior reports, tending to coincide with the original measure's logically-based groupings. Revisions to the measure are suggested.