A couple interesting related posts from Overcoming Bias http://www.overcomingbias.com/2009/12/smoking-followup.html http://www.overcomingbias.com/2009/12/smoki

A couple interesting related posts from Overcoming Bias http://www.overcomingbias.com/2009/12/smoking-followup.html http://www.overcomingbias.com/2009/12/smoking-followup.html http://www.overcomingbias.com/2009/12/animal-smoking-studies.html http://www.overcomingbias.com/2009/12/animal-smoking-studies... Robin's conclusion: "Bottom line: a randomized trial suggests a large smoking harm on bad lungs, which can explain the entire apparently average smoking harm seen elsewhere. My best guess: smokers die ~10-30% more on average, living about 2-6 months less, but there’s much less net harm to strong lung folks."