Is Poor Fitness Contagious? Evidence from Randomly Assigned Friends [report]

Scott Carrell, Mark Hoekstra, James West
2010 unpublished
The increase in obesity over the past thirty years has led researchers to investigate the role of social networks as a contributing factor. However, several challenges make it difficult to demonstrate a causal link between friends' physical fitness and own fitness using observational data. This study uses a randomized treatment design and shows that friends' fitness affects own fitness as well as the probability of being classified as unfit. In equilibrium, our estimates imply that each
more » ... y that each out-of-shape individual creates two additional out-of-shape individuals through their social interactions, thus supporting the provocative notion that obesity spreads on a person-to-person basis.
doi:10.3386/w16518 fatcat:fopgve4w4vbfbilvtdsrqs34oi