ABSTRACT
Much of the research conducted in education, psychology, business, and other disciplines has involved single experiments or studies that rarely provide definitive answers to research questions. We have learned from the previous chapters that researchers seldom replicate their research studies and instead use cross-validation, bootstrap, or jackknife methods to estimate the stability and accuracy of the sample estimate. The world around us is understood better when we discover underlying patterns, trends, and principles, which can result from an accumulation of knowledge gained from several studies on a topic of interest. Consequently, a review of the research literature is invaluable in summarizing and understanding the current state of knowledge about a topic. Rather than rely on subjective judgments or interpretations of the research literature, meta-analysis techniques provide a quantitative objective assessment of the study results.
