Webinar: Gabriel Wallin (Umeå & London School of Economics) May 6
30 mars, 2022
The second webinar of the Spring term is given by Gabriel Wallin
- When: May 6, 2022, 10.00 – 11.00
- Where: Zoom, https://umu.zoom.us/j/67630255319
- Titel: Test score equating of nonequivalent groups using propensity scores
- Abstract: Within educational measurement, one of the main objectives is to compare test-takers in terms of a latent construct. When the construct is some sort of ability, the test score from an assessment test is often used as a proxy for the latent variable. Large-scale standardized testing programs administer tests regularly, typically with all test items being unique for each time. It is thus not possible to fairly compare test-takers without first making an adjustment of their test scores according to possible differences in difficulty between test forms. Such score adjustment is a statistical process known as test score equating. If the test groups to be compared furthermore differ in ability, it is even harder to make fair comparisons since the effects of differences in test form difficulty and of test group ability are intertwined. The gold standard for this situation is to utilize so called anchor items, a set of questions common to both test forms. However, not all testing programs have such items available. In this talk I will discuss equating of test scores under this setting by considering covariates as an alternative source of information to balance the test groups. Specifically, propensity score-based estimators will be presented and demonstrated using both empirical and simulated data to show their potential in test score equating.