external validity, generalizability, relevance
Assessments of whether the results of a study are applicable to the people and treatments of interest depend on evidence outside of the study (e.g. on the mechanism by which a treatment causes an outcome) and judgement.
Uncertainty about the applicability of the results of a study, or systematic review of studies, arises when the study participants, or treatments are different from the people, or treatments of interest, and there is external evidence, or compelling logical reasons for not expecting the same effect.
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