Define and describe IRT. What does it do and how is it used in personnel psychology for developing measures.

Question

What will be an ideal response?

Answer 1

. IRT (Item Response Theory) can be used to conduct a comprehensive item analysis. IRT explains how individual differences on a particular attribute affect the behavior of an individual when he or she is responding to an item (e.g., DeSimone & James, 2015; Stark, Chernyshenko, & Drasgow, 2006). This specific relationship between the latent construct and the response to each item can be assessed graphically through an item-characteristic curve. This curve has three parameters: a difficulty parameter, a discrimination parameter, and a parameter describing the probability of a correct response by examinees with extremely low levels of ability. A test-characteristic curve can be found by averaging all item-characteristic curves. Once the measure is ready to be used, IRT provides the advantage that one can assess each test taker’s ability level quickly and without wasting his or her time on very easy problems or on an embarrassing series of very difficult problems. In view of the obvious desirability of “tailored” tests, we can expect to see much wider application of this approach in the coming years. Also, IRT can be used to assess bias at the item level because it allows a researcher to determine if a given item is more difficult for examinees from one group than for those from another when they all have the same ability. For example, Drasgow (1987) showed that tests of English and mathematics usage provide equivalent measurement for Hispanics and African Americans and for White men and women.