7.7.3.7  No information on variability

If none of the above methods allow calculation of the standard deviations from the trial report (and the information is not available from the trialists) then, in order to perform a meta-analysis, an author may be forced to impute (‘fill in’) the missing data or to exclude the study from the meta-analysis: see Chapter 16 (Section 16.1.3). A narrative approach to synthesis may also be used. It is valuable to tabulate available results for all studies included in the systematic review, even if they cannot be included in a formal meta-analysis.