Achievement tests are commonly used in education to evaluate students' academic performance and proficiency in specific subject areas. However, there is a major problem that threatens the validity of achievement test scores which is test-taking disengagement. Respondents provide answers that are inconsistent with their true ability level and can…

Many low-stakes assessments, such as international large-scale surveys, are administered during time-limited testing sessions and some test-takers are not able to endorse the last items of the test, resulting in not-reached (NR) items. However, because the test has no consequence for the respondents, these NR items can also stem from quitting the…

Process data are becoming more and more popular in education research. In the field of computer-based assessments of collaborative problem solving (ColPS), process data have been used to identify students' test-taking strategies while working on the assessment, and such data can be used to complement data collected on accuracy and overall…

Background: Examinees may not make enough effort when responding to test items if the assessment has no consequence for them. These disengaged responses can be problematic in low-stakes, large-scale assessments because they can bias item parameter estimates. However, the amount of bias, and whether this bias is similar across administrations, is…

Changepoints are abrupt variations in a sequence of data in statistical inference. In educational and psychological assessments, it is pivotal to properly differentiate examinees' aberrant behaviors from solution behavior to ensure test reliability and validity. In this paper, we propose a sequential Bayesian changepoint detection algorithm to…