Item response theory

Alex Reinhart – Updated October 30, 2018 notebooks ·

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.


Pre/post tests