Methodological issues and results described in this paper originated from a Stanford Research Institute (SRI) evaluation of classroom observation data collected in Spring 1973. The main question addressed in this evaluation was whether each of seven Follow Through sponsors had successfully implemented his program in a variety of sites. The steps in the evaluation of implementation included: (1) a determination of the essential program components, (2) a translation of these components in terms of observable phenomena, (3) a measure of the phenomena, and (4) a standard by which to judge implementation. The SRI approach was formulated in the context of the SRI Classroom Observation Instrument in liaison with the Follow Through sponsors. Only program components that could be translated into observation variables were included in the analysis. To focus on the innovative aspects of the Follow Through programs, the standard established to assess implementation was based on comparisons with Non-Follow Through Classrooms. Implementation scores were derived for individual observation variables, and a total implementation score was derived for each classroom. While all sponsors' classrooms had mean total implementation scores that were significantly different from the Non-Follow Through scores, there were differences in the pattern of implementation among sponsors. (Author/RC)