A. Collection of data

1. What was the context of the study?

2. What were the objectives of the study?

3. What was the primary exposure of interest? Was this accurately measured?

4. What was the primary outcome of interest? Was this accurately measured?

5. What type of study was conducted?

6. Describe the source of the study population, process of subject selection, and sample size.

7. Could there have been bias in the selection of study subjects? How likely was this bias?

8. Could there have been bias in the collection of information? How likely was this bias?

9. What provisions were made to minimize the influence of confounding factors prior to the analysis of the data? Were these provisions

sufficient?

B. Analysis of data

1. What methods were used to control confounding bias during data analysis? Were these methods sufficient?

2. What measures of association were reported in this study?

3. What measures of statistical stability were reported in this study?

C. Interpretation of data

1. What were the major results of this study?

2. How is the interpretation of these results affected by information bias, selection bias, and confounding? Discuss both the direction

and magnitude of any bias.

3. How is the interpretation of these results affected by no differential misclassifications? Discuss both the direction and magnitude of

this misclassification.

4. Did the discussion section adequately address the limitations of the study?

5. What were the authors' main conclusions? Were they justified by the findings?

6. To what larger population can the results of this study be generalized?