The CONSORT (Consolidated Standards of Reporting Trials) guidelines,1 now endorsed by many major medical journals (including the Archives of Internal Medicine), chiefly highlight aspects of randomized trial methods that bear on a trial's internal validity—that is, whether the trial reaches the correct conclusion regarding individuals actually enrolled. Among these features are whether assignments are truly made at random, whether the health outcomes of concern are monitored accurately in all participants, and whether a large enough number of such outcomes occur in the participants to yield statistically precise results.
Weiss NS, Koepsell TD, Psaty BM. Generalizability of the Results of Randomized Trials. Arch Intern Med. 2008;168(2):133-135. doi:10.1001/archinternmed.2007.30