Policy makers, practitioners, and social scientists expect to learn from experimental programs, selecting those that work for further development and funding. The conclusion that correctional rehabilitation efforts had “no appreciable effect on recidivism” nearly dismantled further efforts to provide meaningful interventions for offenders. Upon closer examination, several scholars noted that the research had made premature conclusions in asserting that the programs had not worked. In addition to methodological and technical problems with the research, it became clear that some of the evaluated programs had been too difficult to evaluate. The massive costs of evaluating interventions and programs prematurely resulted in serious threats to the future of the programs being evaluated; inaccurate knowledge of what “worked”; inability to identify program changes that would make programs more effective; and a waste of research monies. A research procedure known as the evaluability assessment (EA) was devised to precede an outcome or comprehensive evaluation and to determine whether a program is “evaluable.” The EA helps to determine whether a program has been planned and implemented well enough to be evaluated. If it is determined that the program is not evaluable, an EA should direct program personnel to areas of the program that need further development. In using evaluability as a tool for facilitating optimal program development, it can identify program strengths and weakness and direct further program development energies to areas where they are needed most. The EA cannot serve as a substitute for good planning. In social science planning and evaluation, the most important tasks of planning are targeting criminogenic needs and translating into intermediate objectives, selecting interventions with proven effectiveness, monitoring the integrity of intervention to assure it is being administered, and measuring success. Many programs appear to be hurting themselves when they plan and conduct evaluations too quickly by masking the treatment effect, producing evaluation measures that do not fit program services and clients, and disorganization that results in staff working in different directions. 1 figure, 3 notes, 50 references, appendix