Timeline of meta-analytic methodological innovations
| Innovation | Year | Innovators | Institution | Country | Description |
| Traditional pairwise meta-analysis1 | 1904 | Pearson K | University College London | UK | Combines direct evidence from multiple RCTs comparing the same intervention and comparator (eg, placebo) to strengthen the intervention’s effect estimate relative to that comparator. |
| 1935 | Fisher R | Rothamsted Experimental Station | UK | ||
| 1937 | Cochran W | Rothamsted Experimental Station | UK | ||
| 1976 | Glass GV | University of Colorado | USA | ||
| Adjusted indirect comparison8 | 1997 | Bucher HC Guyatt GH Griffith LE Walter SD | McMaster University | Canada | Combines ORs from multiple RCTs comparing one of two interventions of interest to a common comparator (eg, placebo) to estimate the effects of two interventions that have not been compared directly. |
| Network meta-analysis*10 | 2002 | Lumley T | University of Washington | USA | Combines direct and indirect data from multiple RCTs to compare several sets of pairwise treatment comparisons. |
| Mixed treatment comparison*11 | 2004 | Lu G Ades AE | University of Bristol | UK |
*To our knowledge, Caldwell et al 5 introduced the term multiple treatments meta-analysis to describe the concept of combining direct and indirect evidence to compare multiple treatments connected by a network of RCTs, as seen in both methods.
RCT, randomised controlled trial.