The evaluations studied differed greatly in the steps taken to reduce the risk of displacement. As noted earlier, Michigan's evaluation assigned recipients on the basis of eligibility worker numbers, thereby preserving relationships between caseworkers and ongoing cases in the control group. In contrast, in California's evaluation, recipients in the control group were frequently assigned to different caseworkers and sometimes to different welfare offices, since the control group was a very small proportion of the county caseload and welfare reform policies were implemented for all other cases. The specialized control group caseworkers, fewer in number than the caseworkers administering welfare reform policies, did not always know the language of their clients and were sometimes located
far away from them. The implementation of welfare reform effectively displaced the relationships that had developed between caseworkers and clients. In addition, as a result of being assigned to new caseworkers, control cases were more likely to be "cleaned" (have eligibility reexamined) than experimental cases continuing with the same caseworkers.