Population invariance is a desirable property of test equating which might not hold when significant changes occur in the test population, such as those brought about by the COVID-19 pandemic. This research aims to investigate whether equating functions are reasonably invariant when the test population is impacted by the pandemic. Based on…

Speeded tests set time limits so that few examinees can reach all items, and power tests allow most test-takers sufficient time to attempt all items. Educational achievement tests are sometimes described as "timed power tests" because the amount of time provided is intended to allow nearly all students to complete the test, yet this…

In preparation for online administration of the ACT® test, ACT conducted studies to examine the comparability of scores between online and paper administrations, including a timing study in fall 2013, a mode comparability study in spring 2014, and a second mode comparability study in spring 2015. This report presents major findings from these…