Abstract
This article explored factors related to whether early intervention programs were successful in adopting and implementing a specific approach to providing parent-child groups. Programs were given intensive training and then on-site support over 10 to 12 months. Observations of fidelity of implementation in each of 13 programs were used to select the 2 early intervention sites with the highest and lowest fidelity to the model. A case study approach was then used to examine features that distinguished between these 2 sets of programs. Potential adopters of this and other models, as well as those responsible for helping programs replicate early childhood models, will be able to use this information to make more informed judgments before undertaking replication.