Measurement system analysis (MSA) is the part of applied statistics that attempts to describe, categorize, and evaluate measurement error, improve the usefulness, accuracy, and precision of measurements, and propose methods for developing new and better measurement instruments. An expanded gage repeatability and reproducibility (R&R) study has been conducted which enables subdividing measurement error into various sources. This gage R&R study establishes the measurement error of ear thermometers (ETs). Two different ETs are used. Although both are validated, it is interesting to see whether they influence measurement error. The room was climate controlled so ear temperature measurements cannot be influenced by changes in climate. As body temperature has been shown to fluctuate over time, it was essential to minimize the duration of the experiment. Interestingly, the distribution of ear measurements is negatively skewed for nine out of ten subjects. All subjects seem healthy based on the average temperatures. It is found that the interaction between ear (left or right) and 'subject' significantly induced variation.