Do Social Networks Improve the Effectiveness of Incentive-Based Health Programs

Although studies have shown that financial incentives are effective in promoting healthy behaviors, existing interventions have focused on adults in the workforce (e.g. Kullgren et al. 2013). Given that the school environment can be an effective instrument for behavior change, there is a need to examine incentive-based health programs in late-adolescent age groups. Largescale observational studies with about 9,000 freshmen at California Polytechnic State University (Cal Poly) show that every year of college was associated with a 3% BMI increase, especially among minority populations. Reversing or slowing this dynamic has proven difficult because students entering university are newly independent, not experienced in making their own lifedecisions, and encounter many distractions (Nazmi et. al. 2012). On the other hand, university students are uniquely social and social networks have been shown to be effective in leading to behavioral change. Indeed, emerging evidence on peer networks suggests that health behaviors and outcomes are shared, transferred, and influenced through social ties (Christakis and Fowler, 2007; Cohen-Cohen-Cole and Fletcher, 2008). However, few interventions have been designed to capitalize on the behavioral pathways of social networks. The primary purpose of our intervention study is to determine whether financial incentives, mediated by social network effects, are effective in achieving improved diet quality outcomes as measured by the Healthy Eating Index-2010 (HEI). We will conduct a 3.5-month parallel-design, randomized controlled trial with a racially and ethnically diverse sample of participants who consume food in campus cafeterias. Our findings will provide a unique contribution by testing the efficiency of interventions in structural transmission networks. Given the ubiquitous and increasing existence of social networks, our applications are readily transferrable at relatively low cost to other largescale student populations in elementary, middle, and high schools.