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Differential rater function over time (DRIFT) during student simulations

02 July 2022
Volume 12 · Issue 2



The field of paramedicine continues to advance in scope. Simulation training is frequently used to teach and evaluate students. Simulation examinations are often evaluated using a standardised global rating scale (GRS) that is reliable and valid. However, differential rater function over time (DRIFT) has not been evaluated when using the GRS during simulations.


This study aimed to assess if DRIFT arises when applying the GRS.


Data were collected at six simulation evaluations. Raters were randomly assigned to evaluate several students at the same station. Each station lasted 12 minutes and there was a total of 11 stations. A model to test DRIFT scores was created and was tested against both a leniency and perceptual model.


Of the models explored, one that included students, the rater, and the dimensions had the greatest evidence (−3151 Bayes factors). This model was then tested against leniency (K=−9.1 dHart) and perceptual models (K=−7.1 dHart). This suggests a substantial finding against DRIFT; however, the tested models used a wide parameter so the possibility of a minor effect is not fully excluded.


DRIFT was not found; however, further studies with multiple centres and longer evaluations should be conducted.

The field of paramedicine has evolved considerably over the last three decades. Originally, the role of a paramedic was restricted to patient transportation from the field to a nearby hospital with little medical intervention along the way. Today, paramedics are skilled clinicians who are capable of performing advanced medical and procedural interventions in a prehospital setting (Joyce et al, 2009; Williams et al, 2016).

To ensure that paramedic students are ready to enter the workforce, academic institutions have been adopting novel techniques (Thompson and Houston, 2021).

Simulation training is a hands-on, practical teaching method that has become increasingly used within teaching institutions (McKenna et al, 2015; Van Dillen et al, 2016; Tsai et al, 2020; Thompson and Houston, 2021). It has been established that simulation training is a critical means of improving medical education. Students exposed to simulation acquire more competencies and expertise in practical skills than those whose curriculum does not require simulation training (Van Dillen et al, 2016).

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