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Item Response Theory


3.0 Credit, 3 Lecture, 0 Lab



Concepts, models, and assumptions in IRT, including trait and parameter estimation, scale properties, assessment of model fit, and the use of computer software. Emphasizes applications of IRT to practical testing problems including test construction and revision, adaptive testing, differential item functioning, score equating, vertical scaling, and model-based diagnostic assessment.

Contrast IRT with CTT

Contrast item response theory (IRT) with classical test theory (CTT) and explain the advantages, limitations, and principle uses of each in modern applications of educational and psychological measurement.

IRT Understanding

Demonstrate a working understanding of the basic concepts and principles of item response theory including:

a.    person ability parameters

b.     the different kinds of item parameters

c.     item response functions

d.     information functions and standard errors of estimation

e.     the basic dichotomous and polytomous models and the assumption associated with each  

f.      procedures for assessing model-data fit

g.     commonly used parameter estimation procedures and situations in which the use of each is appropriate or inappropriate

IRT software

Demonstrate proficiency in using modern software to conduct IRT analyses to:

a.    conduct item test analyses and make recommendations for revising, retaining, or replacing specific items

b.     calibrate items for use in computer adaptive tests

c.     equate scores from alternate forms of a test

d.     create vertically scaled tests

e.     detect test items that function differentially for various examinee subgroups

f.      determine appropriate cut-scores and/or performance level descriptions

g.     implement testlet-based scoring.