Abstract
Answer E
A randomised control trial is considered the most appropriate research paradigms for studying an intervention In this study paradigm neither the subject nor the researcher know whether the placebo or trial agent is being used; this reduces bias; the other research paradigms are less favoured in this context
See the two excellent accompanying references for more information.
Groves, T. Different types of clinical evidence and study design. BMJ PowerPoint presentation http://bmjopen.bmj.com/site/about/resources/types_of_study_design.ppt
Centre for evidence-based medicine www.cebm.net/index.aspx?o=1039