Early Childhood Program Evaluations: A Decision-Maker’s Guide
How much impact did the
“Treatment on the treated” impacts
Under certain circumstances, it is also possible to isolate program impacts on the subset of families that actually use the services and compare them to families that did not use similar services. These are sometimes called “treatment on the treated” (or TOT) impacts, and amount to scaling up intent-to-treat estimates in proportion to program take-up. Treatment-on-the-treated estimates address important policy questions about program impacts on the children or families who actually use the services. If program take up is not a concern and you want to concentrate on how a program affects children or families who participate in it, then TOT estimates are most relevant. Finally, when comparing
across studies it is important to compare like with like—ITT with ITT impacts or TOT with TOT impacts.