Meta-analysis: Use of statistical techniques in a systematic review to combine results from multiple individual studies.4, 6, 40 Encompasses a wide variety of methodological approaches whose goal is to quantitatively synthesize and summarize data across a set of studies. Typically, the objective of the analysis is to increase the precision and power of the overall estimated effect of an intervention by producing a single pooled estimate. Sometimes misused as a synonym for systematic reviews. Also called quantitative synthesis.

Multiple comparisons: Performance of multiple analyses on the same data.6 Multiple statistical comparisons increase the probability of making a Type I error (i.e. attributing a difference to an intervention when chance is a reasonable explanation). See also data dredging.