How people evaluate screening value after positive results: an analysis of online forums.

Cancer screening causes harm when people whose health would have been unaffected by cancer are
nonetheless treated. For any screening test, these harms need to be carefully weighed against the
benefits. Research demonstrates that the public and doctors underestimate screening harms. One
explanation may be that people fail to consider the possibility that their health did not benefit from the
screening / treatment. To test this idea we will analyse the content online health forums: the proportion
of people who believe themselves to have benefited will be compared to the proportion of people who
benefit in scientific research.