itempar_grmtree: Extract Item Parameters from GRM Tree

In grmtree: Recursive Partitioning for Graded Response Models

Extract Item Parameters from GRM Tree

Description

Extracts both discrimination parameters and average threshold parameters for each item from all terminal nodes of a graded response model tree. This provides a comprehensive view of item characteristics across different nodes of the tree.

Usage

itempar_grmtree(object, node = NULL, ...)

Arguments

object	A grmtree object.
node	Optional vector of node IDs to extract from. If NULL (default), extracts from all terminal nodes.
...	Additional arguments (currently unused).

Value

A data.frame with item parameters for each item in each node, with columns:

Node	Node ID
Item	Item name
Discrimination	Discrimination parameter (a1)
AvgThreshold	Average of threshold parameters
Thresholds	All threshold parameters as a list column

See Also

grmtree fits a Graded Response Model Tree, grmforest for GRM Forests, fscores_grmtree for computing factor scores, threshpar_grmtree for extracting threshold parameters, discrpar_grmtree for extracting discrimination parameters

Examples

  library(grmtree)
  library(hlt)
  data("asti", package = "hlt")
  asti$resp <- data.matrix(asti[, 1:4])

  # Fit GRM tree with gender and group as partitioning variables
  tree <- grmtree(resp ~ gender + group,
          data = asti,
          control = grmtree.control(minbucket = 30))

  # Get all item parameters
  items <- itempar_grmtree(tree)
  print(items)

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