Generalizability

Generalizability, or external validity, refers to the extent to which the trial results are applicable beyond the patients included in the study. Clinicians typically understand generalizability in terms of how a study might apply to patients in their own practice. Even a perfectly-conducted trial may not be practically useful if there are important differences between your practice and the characteristics of the trial. The importance of such considerations is corroborated by a review (Kennedy-Martin T et al.) of 37 RCTs which found that roughly 70% of identified trials included participants that were not representative of patients in practice.

However, it should be emphasized that the trial population does not need to perfectly represent one’s own practice. Use clinical judgement to determine to what extent differences between your practice and the trial characteristics impact the applicability of the results to your patients.