Table I.
Structure of binary outcomes data set extracted from the Cochrane Database of Systematic Reviews: number of pair-wise intervention comparisons per review, meta-analyses per comparison, studies per meta-analysis and sample sizes of studies.
| N | Min | 25% percentile | Median | 75% percentile | Max | |
|---|---|---|---|---|---|---|
| Number of comparisons | 1991 reviews | 1 | 1 | 1 | 2 | 20 |
| per review | ||||||
| Number of meta-analyses | 3884 comparisons | 1 | 1 | 2 | 5 | 43 |
| per comparison | ||||||
| Number of studies | 14886 meta-analyses | 2 | 2 | 3 | 6 | 294 |
| per meta-analysis | ||||||
| Sample size | 77237 studies | 2 | 50 | 102 | 243 | 1 242 071 |