Nicholas and James are Featured in the NYT again 

 Professor Nicholas Christakis and Professor James Fowler's study on social network and smoking cessation is featured in the New York Times, which is also going to appear in the New England Journal of Medicine this Thursday. Congratulations to them! 

 Their basic findings are that smokers are likely to quit in groups (As Nicholas said, "Whole constellations are blinking off at once.") and that the remaining smokers tend to be socially marginalized.  

 One interesting question I have for their study is that, if friends tend to quit smoking together, will this partly contribute to the simultaneous weight gains among friends, a result Nicholas and James have found last year using the same dataset? In other words, I totally accept that social ties have important impacts on individuals' wellbeing, but if you try to research a certain outcome of wellbeing and do not control for the "contaminating" effects from other outcomes, the estimation of the social network effects on the former outcome could be biased. For example, the weight gains among friends, from this point of view, could be partially resulted from their simultaneous quitting from smoking. Of course, if smokers only consist of a very small fraction of the participants in the studied sample and their weight changes are not too extreme, the bias of the estimation should not invoke a serious problem. 

 See the following link for a glimpse of their study.   

 Study Finds Big Social Factor in Quitting Smoking 
 http://www.nytimes.com/2008/05/22/science/22smoke.html?partner=rssnyt&emc=rss 
  
Sorry for the duplicate if you have noticed this news.