How science takes stock

Policymakers, medical practitioners, and the public alike face a bewildering flood of new and often contradictory scientific studies on almost every topic. Does psychotherapy work, and if so what form works best? Does federal spending on education improve student performance? Whatever the issue, the growth of modern science has often done more to stir up controversy than to establish reliable knowledge. To address this problem, scientists in several fields have developed a sophisticated new methodology called meta-analysis. By numerically combining diverse research findings on a single question, meta-analysis can be used to identify their central tendency and reach conclusions far more reliable than those of any single investigation.

How Science Takes Stock tells the story of meta-analysis through the eyes of its architects and champions, and chronicles its history, techniques, achievements, and controversies. Noted science author Morton Hunt visits key practitioners and recounts their use of meta-analysis to resolve important scientific puzzles and long-standing debates. With each account, Hunt illustrates the major components of the meta-analytic method, reveals strategies for resolving practical and theoretical problems, and discusses the impact of meta-analysis on the science and policy communities.

He demonstrates how the statistical techniques of meta-analysis produce more accurate data than a standard literature review or the old-fashioned process of tallying up the results of each scientific study as if they were votes in an election. Further, Hunt answers skeptics who claim that dissimilarities between studies are often too significant for meta-analysis to be any more than an "apples and oranges" approach.