In the recent past, research into coed prisons has been substantially descriptive or qualitative, viewing cocorrections as one variable in the institutional environment. Evaluation research, which is generally concerned with program effectiveness, has been limited. The most common measurements used in evaluation research include program participation rates, disciplinary infractions, recidivism rates, and social climate scales. From the descriptions of difficulties encountered in developing or implementing research designs, several issues emerge. These issues or problems have hindered past attempts at gathering valid data and must be considered in planning future research. For example, the dispersion of facilities throughout the United States contributes to the problem of acquiring comparative data. Also, the degree to which sexual integration can be isolated, explained, and evaluated apart from the total institutional setting is problematic. Researchers have also faced the problems of program alteration during evaluation, arbitrary administrative changes, and instances of confounding variables or competing hypotheses in cocorrections. Moreover, accurate measurement requires the passage of time; since most coed prisons were established in 1974 and 1975, an insufficient amount of time has passed to allow use of recidivism rates for valid interpretation. In addition, a recent assessment indicated that no coeducational correctional institution had a research office or staff member whose primary function was research or data collection. Interest in systematically documenting the outcomes of cocorrectional policy has also been conspicuously absent. Finally, lack of appropriate measurement instruments and the sensitive nature of issues encountered in coed prisons tend to impede evaluative research. The chapter includes 17 references.