Table 3Additional domains and their definitions

DomainDefinition and ElementsScore and Application
Dose-response associationThis association, either across or within studies, refers to a pattern of a larger effect with greater exposure (dose, duration, adherence).This domain should be considered when studies in the evidence base have noted levels of exposure.

Score as one of two levels:
  • Present: Dose-response pattern observed
  • Undetected: No dose-response pattern observed (dose-response relationship not present or could not be determined)
Plausible confounding that would decrease observed effectOccasionally, in an observational study, plausible confounding would work in the direction opposite that of the observed effect. Had these confounders not been present, the observed effect would have been even larger than the one observed.This additional domain should be considered when plausible confounding exists that would decrease the observed effect.

Score as one of two levels:
  • Present: Confounding factors that would decrease the observed effect may be present and have not been controlled for.
  • Absent: Confounding factors that would decrease the observed effect are not likely to be present or have been controlled for.
Strength of association (magnitude of effect)Strength of association refers to the likelihood that the observed effect is large enough that it cannot have occurred solely as a result of bias from potential confounding factors.This additional domain should be considered when the effect size is particularly large.

Score as one of two levels:
  • Strong: Large effect size that is unlikely to have occurred in the absence of a true effect of the intervention
  • Weak: Small enough effect size that it could have occurred solely as a result of bias from confounding factors

From: Grading the Strength of a Body of Evidence When Assessing Health Care Interventions for the Effective Health Care Program of the Agency for Healthcare Research and Quality: An Update

Cover of Methods Guide for Effectiveness and Comparative Effectiveness Reviews
Methods Guide for Effectiveness and Comparative Effectiveness Reviews [Internet].

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