grmfit: Internal Function: Fit Graded Response Model

In grmtree: Recursive Partitioning for Graded Response Models

Internal Function: Fit Graded Response Model

Description

Fits a graded response model (GRM) to item response data. This is an internal function called by grmtree and is not intended to be used directly.

Usage

grmfit(
  y,
  x = NULL,
  start = NULL,
  weights = NULL,
  offset = NULL,
  ...,
  estfun = FALSE,
  object = FALSE
)

Arguments

y	A matrix of item responses (rows = persons, columns = items)
x	Optional predictor matrix (not currently used)
start	Optional starting values (passed to mirt)
weights	Optional case weights (not currently used)
offset	Optional offset (not currently used)
...	Additional arguments passed to mirt::mirt
estfun	Logical indicating whether to compute empirical estimating functions
object	Logical indicating whether to return the full mirt model object

Value

A list containing:

coefficients	Item parameter estimates
objfun	Negative log-likelihood value
estfun	Empirical estimating functions if requested
object	Full mirt model object if requested

grmtree documentation built on Sept. 2, 2026, 1:07 a.m.