Discussion: Biases in Epidemiological Studies


The Field Epidemiology Manual provides a set of core training materials reflecting the essential competencies required by intervention epidemiologists.

Discussion: Biases in Epidemiological Studies

  • Hi Aileen and Lisa

    Sorry about this, but its crashing again. The first page worked, I made a couple of suggestions, but cant access it from there on. I am using internet explorer



  • Hi Derval,

    There is definitely a problem with the "selection bias and case-control studies" page (it kept crashing on me too), but the others (e.g. Info Bias, Preventing Bias etc) were ok for me earlier, if you would like to try those?

    all the best,


  • Dear Both,

    Really sorry to read about your troubles - and Martin has indeed been looking into this..a response should follow ASAP tomorrow - and if this hinders your meeting the Friday (8th) deadline, then by all means, we will extend it for you.

    Thank you and more to come,


  • The plot showing the random vs systematic error is erroneous. The measure of random error is the standard error, which (regardless of outcome type) is proportional to the inverse square root of sample size. Therefore the plot should actually look like this:

  • Thanks so much Theodore, this is very good. Feel free to modify the article. That is why this is a Wiki: to be improved where needed.

    Great reply!!

  • By the way, I believe Rothman shoUld have a Femwiki account :)
  • OK, replaced the plot with a modified version. I guess even Rothman can make a slight mistake now and then! :)

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