R: Create a dichotomous response model

rpf.drm {rpf} | R Documentation

## Create a dichotomous response model

### Description

For slope vector a, intercept c, pseudo-guessing parameter g, upper bound u, and latent ability vector theta, the response probability function is

P(pick=0|a,c,g,u,th) = 1-P(pick=1|a,c,g,u,th)

P(pick=1|a,c,g,u,th) = g+(u-g)/(1+exp(-(a th + c)))

### Usage

    rpf.drm(factors = 1, multidimensional = TRUE, poor = FALSE)

### Arguments

`factors` | the number of factors
`multidimensional` | whether to use a multidimensional model. Defaults to `TRUE`.
`poor` | if TRUE, use the traditional parameterization of the 1d model instead of the slope-intercept parameterization

### Details

The pseudo-guessing and upper bound parameter are specified in logit units (see `logit`).

For discussion on the choice of priors see Cai, Yang, and Hansen (2011, p. 246).

### Value

an item model

### References

Cai, L., Yang, J. S., & Hansen, M. (2011). Generalized Full-Information Item Bifactor Analysis. Psychological Methods, 16(3), 221-248.

### Examples

    spec <- rpf.drm()
    rpf.prob(spec, rpf.rparam(spec), 0)

[Package rpf version 0.56.1 Index]