Quasi-Experimental Designs in Practice-based Research Settings: Design and Implementation Considerations

Journal Name: 
The Journal of the American Board of Family Medicine
Authors: 
Handley,Margaret A.
Schillinger,Dean
Shiboski,Stephen
Abstract: 

BackgroundAlthough randomized controlled trials are often a gold standard for determining intervention effects, in the area of practice-based research (PBR), there are many situations in which individual randomization is not possible. Alternative approaches to evaluating interventions have received increased attention, particularly those that can retain elements of randomization such that they can be considered "controlled" trials. MethodsMethodological design elements and practical implementation considerations for two quasi-experimental design approaches that have considerable promise in PBR settings - the stepped-wedge design, and a variant of this design, a wait-list cross-over design, are presented along with a case study from a recent PBR intervention for patients with diabetes. ResultsPBR-relevant design features include: creation of a cohort over time that collects control data but allows all participants (clusters or patients) to receive the intervention; staggered introduction of clusters; multiple data collection points; and one-way cross-over into the intervention arm. Practical considerations include: randomization versus stratification, training run in phases; and extended time period for overall study completion. ConclusionSeveral design features of practice based research studies can be adapted to local circumstances yet retain elements to improve methodological rigor. Studies that utilize these methods, such as the stepped-wedge design and the wait-list cross-over design, can increase the evidence base for controlled studies conducted within the complex environment of PBR

9
1
2011
Volume: 
24
Pages: 
589-596