Table 3.

Characteristics of eight updated Cochrane Methodology Reviews

Updated review characteristics	N (%)
Authorship of updated review
Identical to original review [21, 24]	2 (25.0%)
Different authors and different order [26, 28, 33]	3 (37.5%)
Authors added or removed [22, 23, 25]	3 (37.5%)
Number of updates
One [21–25]	5 (62.5%)
Three [26, 28, 33]	3 (37.5%)
Interval between original and updated review
One year [21]	1 (12.5%)
Two years [24]	1 (12.5%)
Three years [28, 33]	2 (25.0%)
Four years [25]	1 (12.5%)
Five years [23]	1 (12.5%)
Eleven years [22, 26]	2 (25.0%)
Methodological topic of included studies
Randomization method [25, 26, 28, 33]	4 (50.0%)
Conflict of interest [23]	1 (12.5%)
Technical editing [21]	1 (12.5%)
Full publication of results [22]	1 (12.5%)
Questionnaires [24]	1 (12.5%)
Conclusions
Same as previous version [21–25]	5 (62.5%)
Different to previous version [26, 28, 33]	3 (37.5%)