How to assess the external validity of therapeutic trials: a conceptual approach

External validity of study results is an important issue from a clinical point of view. From a methodological point of view, however, the concept of external validity is more complex than it seems to be at first glance.Methodological review to address the concept of external validity.External validity refers to the question whether results are generalizable to persons other than the population in the original study. The only formal way to...