Selection bias

Abstract

Selection bias In a recent research article in CMAJ, 1 the study population consists entirely of ill travellers self-reporting to a travel clinic upon their return. It seems likely that this would select patients who were either sufficiently unwell or sufficiently worried about their illness to seek medical attention. In light of this, I find it unsurprising that this study 1 observed a higher incidence of complicated disease than that seen in endemic areas.

Response to “Selection bias”

“…We thank Dr. Jansz 1 for his interest in our surveillance report. 2 We recognize that understanding the intricacies of the CanTravNet data would be difficult without first-hand experience of our network and its patient population.…”