Lecture 7

Question 1

What are the applications of item reponse theory?

Answer 1

1-Creating tests for specific target audience (measuring the IQ of gifted kids)
2-Development of computer adaptive tests (level of items adapted to individuals according to their given answers.)
3-When testing construct bias
4-Investigating the reponse pattern ( reponse bias)

Question 2

What is item response theory?

Answer 2

The latet variable (independent q) predicts the probability of item reponse = 1 (dependent)

1-Common factor model but with ordinal items.
2-Our main focus is items with 2 categories.
3-So we will be using logistic regression.
4-Unobservable trait

Question 3

The qualities of the items?

Answer 3

1-Itemscores are reflective ( causally and directly depend on latent variable.
2- Items are unidimensional
3-The latent variable has a mean of 0 and SD of 1.

Question 4

What do a and b represent in the IRT formula?

Answer 4

1-A and b are parameters and determine the shape of the ICC curve. (they are given estimated by the software)