Wisler "et al", in their review of the "Follow Through" experience, wrote that it was likely that no other educational data has been examined more extensively, excepting the Equality of Educational Opportunity Survey. At least three major reevaluations of the "Follow Through" data exist in the literature: House, "et al." (1978); Bereiter and Kurland (1981); and Kennedy (1981). All largely confirm the original statistical analysis conducted by Abt Associates. Generally, the consensus among most researchers is that structured models tended to perform better than unstructured ones, and that the Direct Instruction and Behavior Analysis models performed better on the instruments employed than did the other models.) Most critiques of the "Follow Through" experiment have tended to focus on the operational and design problems that plagued the experiment. In particular, these critiques note that there was more variation within a particular model than there was from model to model. This problem has largely been attributed to the problem of how to measure the effectiveness of a particular implementation; the measures used were largely qualitative and anecdotal. In some instances, sites were included in the analysis that had ceased to implement specific models, or the model sponsors had serious reservations about the way particular models were implemented.