Therese D. Pigott

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Calculations of the power of statistical tests are important in planning research studies (including meta-analyses) and in interpreting situations in which a result has not proven to be statistically significant. The authors describe procedures to compute statistical power of fixed- and random-effects tests of the mean effect size, tests for heterogeneity(More)
Calculation of the statistical power of statistical tests is important in planning and interpreting the results of research studies, including meta-analyses. It is particularly important in moderator analyses in meta-analysis, which are often used as sensitivity analyses to rule out moderator effects but also may have low statistical power. This article(More)
This meta-analysis synthesized bullying prevention programs’ effectiveness at increasing bystander intervention in bullying situations. Evidence from 12 school-based programs, involving 12,874 students, indicated that overall the programs were successful (Hedges’s g .20, 95% confidence interval [CI] .11 to .29, p .001), with larger effects for high school(More)
This paper reviews methods for handling missing data in a research study. Many researchers use ad hoc methods such as complete case analysis, available case analysis (pairwise deletion), or single-value imputation. Though these methods are easily implemented, they require assumptions about the data that rarely hold in practice. Model-based methods such as(More)
Missing data occur frequently in meta-analysis. Reviewers inevitably face decisions about how to handle missing data, especially when predictors in a model of effect size are missing from some of the identified studies. Commonly used methods for missing data such as complete case analysis and mean substitution often yield biased estimates. This article(More)
Asthma is a chronic illness that affects 5% to 10% or about 5 million children in this country. Morbidity and rising mortality rates are of particular concern in minority children. This study addresses a serious knowledge deficit about the management of asthma in minority children by testing the effect of a school-based asthma education program on(More)
1. When conducting a research synthesis, is it ever appropriate for a C2 reviewer to do a review without statistically integrating the results of studies? If yes, what are the characteristics of the literature that make this permissible?. 5. Should C2 have a role in advancing cross-design synthesis methods (e.g., propensity scoring and alternatives)? What(More)