The social contagion hypothesis: comment on ‘Social contagion theory: examining dynamic social networks and human behavior’

I reflect on the statistical methods of the Christakis–Fowler studies on network‐based contagion of traits by checking the sensitivity of these kinds of results to various alternate specifications and generative mechanisms. Despite the honest efforts of all involved, I remain pessimistic about establishing whether binary health outcomes or product adoptions are contagious if the evidence comes from simultaneously observed data. Copyright © 2012 John Wiley & Sons, Ltd.