Table 5.

Rating up evidence for magnitude of effect using the GRADE approach for certainty assessment (Morgan et al., 2016).

RR, OR*
Magnitude of effect	Definition	Quality of evidence
Large	RR* >2 or < 0.5 (based on direct evidence, with no plausible confounders)	may increase 1 level
Very large	RR* >5 or < 0.2 (based on direct evidence with no serious problems with risk of bias or precision, i.e. with sufficiently narrow confidence intervals)	may increase 2 levels
Other outcome measures
One may be more likely to rate up the quality of evidence because of large or very large magnitude of an effect, when: •effect is rapid •effect is consistent across subjects •previous trajectory of disease is reversed •large magnitude of an effect is supported by indirect evidence

Note: * = for evaluating the magnitude of an effect based on OR, it is suggested to first convert OR to RR.