Comparison of the core questions of the 2 versions of the Instrument for assessing the Credibility of Effect Modification Analyses
| Core question | Version; question no.* | |
|---|---|---|
| Randomized controlled trials | Meta-analyses | |
| Is the analysis of effect modification based on comparison within rather than between trials? | – | 1 |
| For within-trial comparisons, is the effect modification similar from trial to trial? | – | 2 |
| For between-trial comparisons, is the number of trials large? | – | 3 |
| Was the direction of effect modification correctly hypothesized a priori? | 1 | 4 |
| Was the effect modification supported by prior evidence? | 2 | – |
| Does a test for interaction suggest that chance is an unlikely explanation of the apparent effect modification? | 3 | 5 |
| Did the authors test only a small number of effect modifiers or consider the number in their statistical analysis? | 4 | 6 |
| Did the authors use a random-effects model? | – | 7 |
| If the effect modifier is a continuous variable, were arbitrary cut points avoided? | 5 | 8 |
NA = not applicable.
↵* Numbers reflect order of appearance within the full instrument (see Appendices 5 and 6).