Chapter Questions
What are the major advantages of IRT over CTT-IA?
How do you determine the difficulty, discrimination, and pseudo-guessing parameters in IRT? How are they different from CTT-IA?
When might it be preferable to use CTT-IA instead of IRT?
What are the advantages and disadvantages of the 1-PL, 2-PL, and 3-PL IRT models?
What advantages do IRFs (i.e., graphs) have over simply examining the item parameters in table form?
What does it mean to say that item and person parameters are invariant (i.e., locally independent) in IRT models, but not in CTT-IA?
What unique information do IRFs and IIFs provide for test development and revision?