Two substudies were conducted within the School Health Education Evaluation (SHEE) to assess implementation practices and cumulative effects. In both studies, special samples were identified that permitted independent analysis of contributing factors. For the implementation study, teachers who had taught only one year were assessed in their second year to determine what changes they made during implementation and how those changes were related to classroom performance. Teachers taught significantly fewer hours, fewer components of the curriculum, and made more changes. However, the classroom performance, compared with the first year, improved for both knowledge and attitude with a marginal trend toward improvement in self-reported practices. These results suggest that teachers became both more efficient and effective in the second iteration. The cumulative effects study tracked children through different levels of exposure to health instruction across two consecutive grade levels. Using partial classrooms as the unit of analysis, the results revealed that for knowledge, attitudes, and self-reported practices, exposure to two units of School Health Curriculum Project (SHCP) were more effective than one which was, in turn, more effective than no exposure. Analysis of self-reported smoking practices indicated cumulative program effectiveness in reducing both current smoking and future intent to smoke.