Mean and Mean difference are the two key statistical measures used in the statistical analysis. Both are essential for meta-analysis as well. Mean and Mean difference are used for the interpretation of a large set of values into a single number which explains the heterogeneity and variation among the individual values. However, one of a common challenge in meta-analysis is the unavailability of this data (mean and standard deviation).
Q & A Forum
Meta Analysis
Q: How is pooled SD calculated when combining two subgroups into one?

- If homogeneous variance is assumed, the Cohen method can be used to pool SD (Formula 15).

- If means of the subgroups are available, the method outlined in the Cochrane Handbook should be used, as it accounts for mean differences (Formula 16).
