TY - JOUR T1 - Randomised controlled trials in primary care: scope and application. JF - British Journal of General Practice JO - Br J Gen Pract SP - 746 LP - 751 VL - 52 IS - 482 AU - Aziz Sheikh AU - Liam Smeeth AU - Richard Ashcroft Y1 - 2002/09/01 UR - http://bjgp.org/content/52/482/746.abstract N2 - There is now widespread acknowledgement of the absence of a sound evidence base underpinning many of the decisions made in primary care. Randomised controlled trials represent the methodology of choicefor determining efficacy and effectiveness of interventions, yet researchers working in primary care have been reluctant to use intervention studies, favouring observational study designs. Unfamiliarity with the different trial designs now available, and the relative advantages and disadvantages conferred by each, may be one factor contributing to this paradox. In this paper, we consider the principal trial designs available to primary care researchers, discussing the contexts in which a particular design may prove most useful. This information will, we hope, also prove useful to primary care clinicians attempting to interpret trial findings. ER -