Do we really want a program evaluation strategy based solely on individualized goals?

Abstract
Goal attainment scaling is a program evaluation technique that measures program success using individualized client goals rather than the same measuring instrument for all clients. Although the reliability of the goal attainment scales is generally acceptable, such scales have not exhibited satisfactory validity. Also when clients have not been assigned to programs randomly, evaluations comparing two or more programs using goal attainment scales are potentially more biased than evaluations that use the same outcome measure for all clients. Thus since goal attainment scaling does have therapeutic value, program evaluators should adopt a multivariate assessment strategy combining goal attainment scaling with uniform measuring instruments.