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liboscats Reference Manual | ![]() |
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Top | Description | Object Hierarchy | Properties |
struct OscatsModelGpc;
The Generalized Partial Credit Model is a special case of Bock's Nominal Response Model (OscatsModelNominal): P(X=k|theta) = f_k(theta)/[1+sum_j f_j(theta)], where f_j(theta) = sum_i a_i theta_i - b_j + sum_l d_l covariate_l, a_i is the discrimination for dimension i, b_j is the scaled option difficulty, and f_0(theta) = 0. Responses are numbered 0, 1, ..., Ncat-1. Note that all options share the same parameters for the covariates. No distance metric is currently provided, but see Ali (2011) for possibilities.
Parameter names: Diff.k, Discr.DimName
References:
"Ncat"
property"Ncat" guint : Read / Write / Construct Only
The number of response categories in the IRT model, numered 0, 1, ..., Ncat-1. The default number of categories is 3, which is also the minimum.
Allowed values: >= 3
Default value: 3