1. A tool for the classification of study designs in systematic reviews of interventions and exposures Meera Viswanathan, PhD for the University of Alberta EPC AHRQ Conference September 2009

2. Steering Committee Ken Bond, UAEPC Donna Dryden, UAEPC Lisa Hartling, UAEPC Krystal Harvey, UAEPC P. Lina Santaguida, McMaster EPC Karen Siegel, AHRQ Meera Viswanathan, RTI-UNC EPC

3. Background EPC reports, particularly comparative effectiveness reviews, are increasingly including evidence from nonrandomized and observational designs In systematic reviews, study design classification is essential for study selection, risk of bias assessment, approach to data analysis (e.g., pooling), interpretation of results, grading body of evidence Assignment of study designs is often given inadequate attention

4. Objectives 1.Identify tools for classification of studies by design 2.Select a classification tool for evaluation 3.Develop guidelines for application of the tool 4.Test the tool for accuracy and inter-rater reliability

5. Objective 1: Identification of tools 31 organizations/individuals contacted 11 organizations/individuals responded 23 classification tools received 10 tools selected for closer evaluation 1 tool selected for modification and testing

6. Objective 2: Tool selection Steering Committee ranked tools based on: –Ease of use –Unique classification for each study design –Unambiguous nomenclature and decision rules/definitions –Comprehensiveness –Potentially allows for identification of threats to validity and provides a guide to strength of inference –Developed by a well-established organization

7. Objective 3: Tool development Three top-ranked tools: –Cochrane Non-Randomised Studies Methods Group –American Dietetic Association –RTI-UNC Incorporated positive elements of other tools Developed glossary

8. Objective 4: Testing round 1 Overall agreement (30 studies, 6 testers) κ=0.26 (fair) Graduate level training complete (3 testers) κ=0.38 (fair) Graduate level training in progress (3 testers) κ=0.17 (slight) Item agreement: 6/6 testers agreed0 5/6 testers agreed7 (23%) 4/6 testers agreed5 (17%) 3/6 testers agreed9 (30%) 2/6 testers agreed8 (27%) No agreement1 (3%)

9. Objective 4: Testing round 1 No clear patterns in disagreements Disagreements occurred at all decision points Tool vs. studies Variations in application of the tool

10. Objective 4: Reference standard Overall agreement (30 studies, 3 raters) κ=0.33 (fair) Item agreement: 3/3 raters agreed7 (23%) 2/3 raters agreed14 (47%) No agreement9 (30%)

11. Objective 4: Testing round 2 Overall agreement (15 studies, 6 testers) κ=0.45 (moderate) Graduate level training complete (3 testers) κ=0.45 (moderate) Graduate level training in progress (3 testers) κ=0.39 (fair) Item agreement: 6/6 testers agreed3 (20%) 5/6 testers agreed2 (13%) 4/6 testers agreed6 (40%) 3/6 testers agreed2 (13%) 2/6 testers agreed2 (13%) No agreement0

12. Discussion Moderate reliability, low agreement with reference standard Studies vs. tool as source of disagreement –tool not comprehensive, e.g., quasi-experimental designs –studies challenging, e.g., sample of difficult studies, poor study reporting To optimize agreement and reliability: –training in research methods –training in use of tool –pilot testing –decision rules

13. Next Steps Test within a real systematic review Further testing for specific study designs Further evaluation of differences in reliability by education, training, and experience

14. Acknowledgments Ahmed Abou-Setta Liza Bialy Michele Hamm Nicola Hooton David Jones Andrea Milne Kelly Russell Jennifer Seida Kai Wong Ben Vandermeer (statistical analysis)

15. Questions? University of Alberta EPC Edmonton, Alberta, Canada