Approach

Abstract

By this point, the reader will have gathered that we believe the literature on LTR is disappointingly fragmented, surprisingly barren of a theory-guiding framework for yielding fruitful, testable hypotheses, and of limited real-world application. As pointed out, there are essentially separate literatures resulting from researchers representing different outlooks, communities, and basic and applied requirements. When we began this review, our desire was to conduct a meta-analysis, which is an integrated-review approach that goes well beyond the typical chronologically-assembled, narrative description of a body of related research. Glass (1977) coined the term meta-analysis, in response to what he saw as a demand for more sophisticated techniques of measurement and statistical analysis, to describe an approach which could be applied to the accumulated findings of dozens or even hundreds of studies.