rpf.nrm: Create a nominal response model
Description
This function instantiates a nominal response model. The
T matrix must be an invertible square matrix of dimension
outcomes-1. As a shortcut, either T matrix can be
specified as "trend" for a Fourier basis or as "id" for
an identity basis.Usage
rpf.nrm(outcomes = 3, factors = 1, T.a = "trend",
T.c = "trend")Arguments
outcomes
The number of choices available
factors
the number of factors
T.a
the T matrix for slope parameters
T.c
the T matrix for intercept parameters
References
Thissen, D., Cai, L., & Bock, R. D. (2010). The Nominal
Categories Item Response Model. In M. L. Nering & R.
Ostini (Eds.), Handbook of Polytomous Item Response
Theory Models (pp. 43--75). Routledge.