Yeates, P, Cope, N, Hawarden, A et al. (3 more authors) (2019) Developing a video‐based method to compare and adjust examiner effects in fully nested OSCEs. Medical Education, 53 (3). pp. 250-263. ISSN 0308-0110
Abstract
Background: Although averaging across multiple examiners’ judgements reduces unwanted overall score variability in objective structured clinical examinations (OSCE), designs involving several parallel circuits of the OSCE require that different examiner cohorts collectively judge performances to the same standard in order to avoid bias. Prior research suggests the potential for important examiner‐cohort effects in distributed or national examinations that could compromise fairness or patient safety, but despite their importance, these effects are rarely investigated because fully nested assessment designs make them very difficult to study. We describe initial use of a new method to measure and adjust for examiner‐cohort effects on students’ scores.
Methods: We developed video‐based examiner score comparison and adjustment (VESCA): volunteer students were filmed ‘live’ on 10 out of 12 OSCE stations. Following the examination, examiners additionally scored station‐specific common‐comparator videos, producing partial crossing between examiner cohorts. Many‐facet Rasch modelling and linear mixed modelling were used to estimate and adjust for examiner‐cohort effects on students’ scores.
Results: After accounting for students’ ability, examiner cohorts differed substantially in their stringency or leniency (maximal global score difference of 0.47 out of 7.0 [Cohen's d = 0.96]; maximal total percentage score difference of 5.7% [Cohen's d = 1.06] for the same student ability by different examiner cohorts). Corresponding adjustment of students’ global and total percentage scores altered the theoretical classification of 6.0% of students for both measures (either pass to fail or fail to pass), whereas 8.6–9.5% students’ scores were altered by at least 0.5 standard deviations of student ability.
Conclusions: Despite typical reliability, the examiner cohort that students encountered had a potentially important influence on their score, emphasising the need for adequate sampling and examiner training. Development and validation of VESCA may offer a means to measure and adjust for potential systematic differences in scoring patterns that could exist between locations in distributed or national OSCE examinations, thereby ensuring equivalence and fairness.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018 The Authors. Medical Education published by Association for the Study of Medical Education and John Wiley & Sons Ltd; This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. https://creativecommons.org/licenses/by-nc/4.0/ |
Keywords: | Assessment; OSCE; Assessor variability; Psychometrics |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Education, Social Sciences and Law (Leeds) > School of Education (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 13 Nov 2018 13:32 |
Last Modified: | 25 Jun 2023 21:35 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1111/medu.13783 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:138425 |