Meta-Analysis

Meta-analysis is the estimation of a population effect size by calculating a weighted estimate of that effect across all the obtainable studies of that effect. Meta-analysis, like many statistical and methodological techniques, emerged to solve a problem. In the 1970s, when various meta-analysis methods began appearing on the scene, social scientists attempting to summarize the findings in a research area were often faced with just as many confirmations as disconfirmations of the existence of basic relationships among variables. The problem was and is that any given estimate of the relationship between two variables that is produced by a single study is plagued by many sources of error. These sources of error can cause a collection of studies to appear more inconsistent than they ...