Did the study ask a clearly focussed research question?
What is the Population considered:
What is the Intervention given:
Was the study type clearly stated?
Were all of the relevant outcomes (dependent variables) assessed?
Were all other external factors (including confounders) considered?
Was the sampling frame and sampling method described? Were there any potential problems that might affect internal validity?
Was allocation to treatment arms truly random?
Was the treatment arm blinded to patients?
Were all patients accounted for in the final analysis?
Were all patients analysed using "intention-to-treat"?