Addi van Bergen

166 • The persons that are lost to follow-up may have different outcomes than those available for assessment • In an open or dynamic cohort, was there anything special about the outcome of the people leaving, or the exposure of the people entering the cohort? (B) What are the result? 7. What are the results of this study? Yes Can’t tell No HINT: Consider • What are the bottom line results? • Have they reported the rate or the proportion between the exposed/ unexposed, the ratio/the rate difference? • How strong is the association between exposure and outcome (RR,)? • What is the absolute risk reduction (ARR)? 8. How precise are the results? HINT: Look for the range of the confidence intervals, if given. 9. Do you believe the results? Yes Can’t tell No HINT: Consider • Big effect is hard to ignore! • Can it be due to bias, chance or confounding? • Are the design and methods of this study sufficiently flawed to make the results unreliable? • Bradford Hills criteria (e.g. time sequence, dose-response gradient, biological plausibility, consistency) (C) Will the results help locally? 10. Can the results be applied to the local population? Yes Can’t tell No HINT: Consider whether • A cohort study was the appropriate method to answer this question • The subjects covered in this study could be sufficiently different from your population to cause concern • Your local setting is likely to differ much from that of the study • You can quantify the local benefits and harms