Assessing cause and effect from trials: a cautionary note.
Howel
D
D
Medical School, Newcastle upon Tyne, United Kingdom.
Bhopal
R
R
D015984:Causality; D002986:Clinical Trials as Topic / Q000379:methods*; D015986:Confounding Factors, Epidemiologic; D003627:Data Interpretation, Statistical; D004812:Epidemiologic Methods; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome