Oft werden Fragen zur Statistik gestellt. Nach unserer Erfahrung sind Antworten darauf besonders häufig in den folgenden Abschnitten des Cochrane Handbook for Systematic Reviews of Interventions zu finden:

9.2      Types of data and effect measures

9.2.3    Effect measures for continuous outcomes
9.2.3.1  The mean difference (or difference in means) (WMD)
9.2.3.2  The standardized mean difference (SMD)

9.2.4    Effect measures for ordinal outcomes and measurement scales

9.4.5.2  Meta-analysis of change scores

9.5      Heterogeneity

9.5.4    Incorporating heterogeneity into random-effects models

7.7      Extracting study results and converting to the desired format

7.7.3    Data extraction for continuous outcomes
7.7.3.1  Post-intervention versus change from baseline
7.7.3.2  Obtaining standard deviations from standard errors and confidence intervals for group means
7.7.3.3  Obtaining standard deviations from standard errors, confidence intervals, t values and P values for differences in means
7.7.3.4  Transformations and skewed data
7.7.3.5  Medians and interquartile ranges

16.1.3   Missing standard deviations

16.1.3.1 Imputing standard deviations
16.1.3.2 Imputing standard deviations for changes from baseline

16.2     Intention-to-treat issues

16.5     Studies with more than two intervention groups

16.5.4   How to include multiple groups from one study