![]() |
![]() |
![]() |
liboscats Reference Manual | ![]() |
---|---|---|---|---|
Top | Description | Object Hierarchy | Properties |
struct OscatsModelNominal;
The Nominal Response IRT model: P(X=k|theta) = f_k(theta)/[1+sum_j f_j(theta)], where f_j(theta) = sum_i a_ij theta_i - b_j + sum_l d_l covariate_l, a_ij are the option discriminations for each dimension, b_j is the scaled option difficulty, and a_i0 = b_0 = 0. Responses are numbered 0, 1, ..., Ncat-1. Note that all options share the same parameters for the covariates. Distance is defined as: min_j abs(f_j(theta)).
Parameter names: Diff.j, Discr.j.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