Seminar in Psychometrics

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Equating nonequivalent test groups using propensity scores

Date and time: April 27, 2021 (3:40 PM CET)
Place ICS CAS room 318, Pod Vodárenskou věží 2, Prague 8, also on Zoom.

Abstract. For standardized assessment tests, scores from different test administrations are comparable only after the statistical process of equating. In this talk I will discuss equating of test scores when the test groups differ in their ability distributions. The equating procedures, constructed to only adjust scores due to differences in difficulty level of the test forms, thus risk to also adjust for the ability differences. The gold standard for this situation is to utilize a set of common items in the equating procedure. However, not all testing programs have common items available. This presentation considers this setting. In the absence of common items, background information about the test-takers will be gathered in a scalar function known as the propensity score, and the test forms will be equated with respect to this score. This method will be demonstrated using both empirical and simulated data.

Gabriel Wallin,
London School of Economics and Political Science

Gabriel Wallin is a Research Fellow at the Department of Statistics at London School of Economics and Political Science where he belongs to the Social Statistics research group. Previously, he was a postdoctoral researcher at the French national research institute Inria. He received his PhD in 2020 from the Department of Statistics at Umeå University, Sweden, under the supervision of Professor Marie Wiberg.

Research of Dr. Wallin is centered around fairness and interpretability of statistical models and machine learning algorithms for the social and behavioral sciences. So far, he has addressed these topics by developing new methodology for e.g. model-based clustering, multivariate outlier detection and exploratory factor analysis.