Is there a hierarchy of methods in clinical research?
Vandenbroucke
J P
JP
University Hospital, Leiden, The Netherlands.
D002986:Clinical Trials as Topic / Q000379:methods; D015331:Cohort Studies / Q000379:methods; D005069:Evaluation Studies as Topic / Q000379:methods*; D006801:Humans; D011446:Prospective Studies / Q000379:methods; D011897:Random Allocation; D012189:Retrospective Studies / Q000379:methods