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Outlier (Evidence Rating Element)
An unusually high or low effect size. When combining effect sizes from various evaluations, extreme outliers can potentially distort the overall mean effect size. This is a dimension in the Practices Scoring Instrument that assesses whether the meta-analysis checks for effect size outliers in the data. Note that this item refers to outlying effect sizes included in the meta-analysis, not the outlying data in the evaluation studies that contributed to the meta-analysis.