Much of the currently available evidence on the causal effects of public prekindergarten programs on school readiness outcomes comes from studies that use a regression-discontinuity design (RDD) with the age cutoff to enter a program in a given year as the basis for assignment to treatment and control conditions. Because the RDD has high internal…

In an effort to maintain internal validity while maximizing the generalizability of evaluation results, the theory-testing methodology that links program activities to outcomes (program theory) is proposed. To evaluate a program by explicating and testing the program theory is to perform evaluation as theory testing. (PN)

External and implementation factors and their potential threats to field test validity and the practical realities of the field testing process on results are discussed. External factors include site selection, negotiations, contracts, site monitoring, training, and type of product. Implementation factors include motivation, dependence on local…

A study of school district uses of evaluation and test data is used to illustrate the variety of ambiguities that can appear in qualitative data. Rules of evidence to distinguish valid and potentially nonvalid testimony are proposed. Uses of testimony in evaluation are discussed. (BS)

A model is described which illustrates two general uses of multiple analyses to evaluate quasi-experiments: obtaining estimates of the treatment effect, and checking the validity of the experiment. (MH)