All 24 of Maryland's county school systems participated in a voluntary school improvement program that involved the adoption and implementation of one or more of four research-based, instructional processes: Active Teaching, Mastery Learning, Student Team Learning, and Teaching Variables. A 5-year study of this program produced findings on a number of research topics. Findings in two of these topic areas are discussed in this paper: identification of the characteristics associated with institutionalization of innovations, and identification of the factors best predicting the institutionalization of innovations at the school and district levels. The paper briefly reviews related research, then describes the study methodology. Data collection methods used in the 180 schools involved in the program included analyzing local and state documents, observing training events and classroom implementation activities, evaluating annual questionnaire responses from representative program participants, and interviewing project coordinators and implementers. Successful institutionalization was associated with three types of factors: procedural, policy, and organizational. The strongest predictors of institutionalization were administrative support and instructional gain. Districtwide institutionalization correlated strongly with school institutionalization. Institutionalization failed where there was little evidence of instructional gain in the first year and where staff, program, or organizational changes were prevalent. (PGD)