Meta-analysis is revolutionizing the process of developing cumulative knowledge in the social sciences--and in finance, medicine, and other disciplines. It has essentially created a new epistemology. The use of meta-analysis has expanded exponentially in most research literature in recent years. This book is the most comprehensive treatment to date of modern meta-analysis methods available. John E. Hunter and Frank L. Schmidt--both recognized experts in meta-analysis--present clear and detailed descriptions of meta-analysis methods, with extensive examples that clarify the applications of these methods. New methods for correcting statistical artifacts not previously addressed are presented for both correlational and experimental studies.