Meta-Analyses of Gifted Education

Meta-analysis is a quantitative method of summarizing research results on a given topic. General steps in a meta-analysis include stipulating methodological criteria that studies must meet to be included; using replicable criteria to locate as many qualifying studies of the topic as possible; and quantifying the results of the studies, using a common metric so that the direction and magnitude of findings across studies can be statistically determined. This metric is an effect size, which expresses differences between groups in standard deviation units. The range of possible values is approximately +3.00 to −3.00. Commonly used guidelines indicate that effect sizes are negligible below 0.2, small from 0.2 to 0.5, medium from 0.5 to 0.8, [Page 563]and large at or above 0.8. Meta-analyses have been used ...