Observer heterogeneity can be thought of as a confounding variable

The study published in the April 2016 issue of Asian Biomedicine recruited 2 different sets of observers to perform triage assessments. We know that each observation is subjected to an error. The error has 2 varieties including interobserver variation and intraobserver variation. So effort must be devoted to reduce these errors. The methodology reported may suffer from both intraobserver and interobserver error substantially.