Thomas D. Cook

1. Experiments and Generalized Causal Inference 2. Statistical Conclusion Validity and Internal Validity 3. Construct Validity and External Validity 4. Quasi-Experimental Designs That Either Lack a Control Group or Lack Pretest Observations on the Outcome 5. Quasi-Experimental Designs That Use Both Control Groups and Pretests 6. Quasi-Experimentation: Interrupted Time Series Designs 7. Regression Discontinuity Designs 8. Randomized Experiments: Rationale, Designs, and Conditions Conducive to Doing Them 9. Practical Problems 1: Ethics, Participant Recruitment, and Random Assignment 10. Practical Problems 2: Treatment Implementation and Attrition 11. Generalized Causal Inference: A Grounded Theory 12. Generalized Causal Inference: Methods for Single Studies 13. Generalized Causal Inference: Methods for Multiple Studies 14. A Critical Assessment of Our Assumptions

Evaluation researchers, traditionally considered to be users of quantitative methods, are now actively exploring the qualitative aspects of the performance of the programmes they are evaluating. Rather than argue the validity of either the quantitative or the qualitative approach, most of the noted contributors to this volume conclude that both are required for comprehensive evaluation.

A decade ago, the Society of Prevention Research (SPR) endorsed a set of standards for evidence related to research on prevention interventions. These standards (Flay et al., Prevention Science 6:151-175, 2005) were intended in part to increase consistency in reviews of prevention research that often generated disparate lists of effective interventions due to the application of different standards for what was considered to be necessary to demonstrate effectiveness. In 2013, SPR's Board of Directors decided that the field has progressed sufficiently to warrant a review and, if necessary, publication of "the next generation" of standards of evidence. The Board convened a committee to review and update the standards. This article reports on the results of this committee's deliberations, summarizing changes made to the earlier standards and explaining the rationale for each change. The SPR Board of Directors endorses "The Standards of Evidence for Efficacy, Effectiveness, and Scale-up Research in Prevention Science: Next Generation."