Factors related to the decisions of schools to adopt or not adopt an innovation in science education were studied. The investigations tested a five-factor model of the adoption process which was developed by the author and others during a previous investigation. Data were collected from a sample of 219 American physics teachers who had attended Project Physics summer institutes in 1968 or 1969. Comparison of questionnaire responses of a random national sample of physics teachers with those of institute attenders showed strong similarities. Data on 45 variables were collected. Factor analysis eestablished the replicability of predicted clusters of intercorrelated variables. Computer stopping criteria caused extra clusters to be identified. Although the age of the teacher was independent of the eight clusters established, age was significantly and monotonically related to adoption (adoption being more likely by younger teachers). Recommendations were made concerning appropriate actions that could be taken with good effect by concerned educators and funders to expedite the adoption of Project Physics (and, perhaps, other courses) if the relationships are causal. (Author/EB)