Systematic reviews and meta-analyses

The Childhood Obesity Intervention Cost-Effectiveness Study (CHOICES) has developed intervention logic models detailing intermediate steps between intervention recruitment and health outcomes and has used these logic models to structure systematic reviews and meta-analyses to connect evidence along multiple pathways. A standardized systematic review process across the evaluated interventions thus incorporated a range of intermediate behavioral outcomes into a coherent decision analysis model.

Image showing logic model exampleLogic model example:
This logic model represents the expected effects of interventions (policies and programs) on short-term behavior change (like purchasing certain foods, participating in certain programs), how that will impact intermediate behavior change (e.g., how much physical activity someone gets or how much their caloric intake changes), the impact of that behavior change on BMI, and how changes in BMI might impact disease risk and related health outcomes.

Why perform a systematic review?

Because the systematic review process is detailed and often requires screening by at least two individuals, it reduces bias inherent to the views of one reviewer. By summarizing the evidence through the abstraction of similarly designed interventions, reviewers improve the power of the analysis, assess generalizability and effectiveness, and identify areas where further research is warranted. Additionally, systematic reviews provide the foundation for meta-analyses which can lead to more quantitative effect estimates.

A number of studies have examined the relationship between menu calorie labeling and the calories consumers ordered or purchased in a variety of settings with differing results. To get a combined effect estimate for modeling the cost effectiveness of the federal menu labeling policy, CHOICES researcher Dr. Michael Long conducted a systematic review and meta-analysis. While the meta-analysis evidence does not support a significant impact on calories ordered, menu calorie labeling is a relatively low-cost education strategy that may lead consumers to purchase slightly fewer calories.

Resources
Standards for performing a systematic review can be found through the websites of the Cochrane Collaboration, PRISMA, the Institute of Medicine and the Guide to Community Preventive Services.