Wichtige Abschnitte aus dem Reviewers' Handbook zu speziellen statistischen Fragen

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  The mean difference (or difference in means) (WMD)  The standardized mean difference (SMD)

9.2.4    Effect measures for ordinal outcomes and measurement scales  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  Post-intervention versus change from baseline  Obtaining standard deviations from standard errors and confidence intervals for group means  Obtaining standard deviations from standard errors, confidence intervals, t values and P values for differences in means  Transformations and skewed data  Medians and interquartile ranges

16.1.3   Missing standard deviations Imputing standard deviations 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