Item response theory

Alex Reinhart – Updated February 21, 2019 notebooks · refsmmat.com

Item response theory is used to model student answers to assessment questions. A typical IRT model might look like this:

\operatorname{logit}(\Pr(X_{s,i} = 1)) = \alpha_i (s_s - d_i)

where X_{s,i} is 1 if student s gets question i correct. This model has a student ability parameter s_s and a question difficulty parameter d_i, as well as an item discrimination parameter \alpha_i giving the slope of the curve. Different IRT models may have more or fewer parameters.

See also Assessment, Cognitive task analysis.

Overview

Pre/post tests