Add new comment

Comment: 

As the paper discusses, the fact that some of the smokers quit before e-cigarettes became available biases the results toward the null.   This bias means that if using e-cigarettes depresses quitting, we will underestimate how much it depresses quitting and if using e-cigarettes facilitates quitting, we will understimate the benefit.  The fact that we found depressed quitting despite this bias increases the confidence that we can have in the conclusion that use of e-cigarettes is associated with less quitting.  The paper discusses this issue in detail.

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.