This article focuses on issues related to implementing school-based social and character development programs in the context of a large multiprogram evaluation study funded by the Institute of Education Sciences and the Centers for Disease Control and Prevention. Implementation analysis is a relatively new but important research area. The first section describes why this analysis is especially important when null results are obtained. It is also noted that not only does the intervention need to be documented but activities at the comparison site require explication. The wide range of implementation methods used at four of the seven sites in the Social and Character Development Research Program is described and difficulties in studying implementation at multiple sites are discussed. (Contains 8 tables.)