An impact evaluation of the Spanish/English component of the federal Bilingual Education Program (BEP) was done by the American Institutes for Research (AIR) between 1974-76. The AIR evaluation took three years, cost $2 million, and examined many aspects of the BEP. This paper explores the influence of the AIR evaluation on the 1978 reauthorization of the BEP. The evaluation had a greater influence on the Executive Branch then on Congress. The Executive Branch institutionalizes solicitation and utilization of evaluation to a greater degree than does Congress. Because Congress must deal with the entire spectrum of legislation, it must amalgamate more information--of a different nature--than the Executive. Congress placed greater weight on the media and constituent testimony then on the AIR evaluation findings in developing Title VII's 1978 reauthorization. However, as long as the issues which were addressed in the AIR evaluation remain important issues in the BEP, the findings of that evaluation will continue to influence the incremental evolution of bilingual education policy. (Author/RL)