This phase of the downstate Illinois bilingual education program included: locating all past data still in existence in 1976; determining what data were actually retrievable and usable; reporting on these data retrospectively; and finally, collecting new data for a continuing longitudinal study. There were 44 school districts with 4,579 students in the database, and information on 273 variables including many different tests and scales. However, only 204 pupils in grades 3 and 4 with at least 3 years of bilingual education could be used in the experimental group, and 109 pupils in the control group were just starting in the bilingual program. Achievement test scores indicated that students with more years in the program were stronger in both the productive English skills (speaking and writing) and the receptive skills (listening and reading). It appeared that bilingual schooling enhanced conceptual development. However, bilingual schooling did not appear to enhance native language skill in all areas; and it appeared that attitudes toward self, school, and community were negatively influenced by years of bilingual schooling. Language use in the home affected native language proficiency. The author regrets that lack of rigor in experimental design makes interpretation of the findings subject to debate. Questionnaires in English and Spanish, as well as resulting statistical data are appended. (CTM)