Sample interview questions: Can you explain the concept of differential item functioning (DIF) and how it is assessed in personality assessments?
Sample answer:
Differential item functioning (DIF) is a statistical concept used in psychometrics to examine the extent to which different groups of individuals respond differently to specific items within a personality assessment. It refers to situations where examinees from different groups, such as gender, age, or cultural background, with the same underlying trait level have different probabilities of endorsing or responding to a particular item.
Assessing DIF in personality assessments is crucial to ensure fairness and equality in test administration. It allows us to investigate whether certain items are more or less biased towards specific groups, which could potentially lead to inaccurate interpretations and unfair treatment for individuals belonging to those groups.
To assess DIF in personality assessments, various statistical methods are employed. One commonly used technique is the Mantel-Haenszel (MH) method, which compares the item responses of different groups while controlling for the overall ability level of the examinees. The MH method identifies DIF by examining whether the probability of endorsing an item is significantly different for the two groups, even when accounting for their overall trait level.
Another widely used approach is the item response theory (IRT) framework, which models the relationship between an individual’s latent trait level and their probability of endorsing an item. In this framework, DIF can be assessed using methods such as logistic regression or the likeliho… Read full answer