Sample interview questions: Can you explain the concept of differential item functioning (DIF) and how it is assessed in intelligence testing?
Sample answer:
Differential Item Functioning (DIF)
DIF refers to the difference in performance between two groups on a test item after controlling for overall test score. It assesses whether an item exhibits bias by measuring how consistently it discriminates between high and low performers within each group.
Assessing DIF in Intelligence Testing
In intelligence testing, DIF is typically assessed through statistical methods, such as:
- Mantel-Haenszel (MH) Method: Compares the odds of answering an item correctly for different groups while controlling for overall test score.
- Logistic Regression: Models the probability of answering an item correctly as a function of group membership and other covariates, such as overall ability.
- Item Response Theory (IRT) Methods: Estimate item parameters and assess DIF by comparing the item’s difficulty and discrimination between groups.
Interpretation of DIF Results
DIF can be categorized as:
- Uniform DIF: Item difficulty differs between groups, indicating potential bias.
- Non-uniform DIF: Item… Read full answer