This digest addresses the role of evaluation and its basic logic, and provides a description of how the field is structured. In order to reach evaluative conclusions it is usually necessary to establish or identify factual promises and value premises. To obtain the required kind of overall evaluative conclusion, it is typically necessary to…

Meta-analysis is a collection of systematic techniques for resolving apparent contradictions in research findings. Meta-analysts translate results from different studies to a common metric and statistically explore the relations between study characteristics and findings. Since G. Glass first used the term "meta-analysis" in 1976, it has…