grmtree (version 0.1.0)

discrpar_grmtree: Extract Discrimination Parameters from GRM Tree

Description

Extracts discrimination parameters (slope parameters) for each item from all terminal nodes of a graded response model tree. The discrimination parameter indicates how well an item distinguishes between respondents with different levels of the latent trait.

Usage

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

Value

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

Node

Node ID

Item

Item name

Discrimination

Discrimination parameter (a1)

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).

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, itempar_grmtree for extracting item parameters

Examples

# \donttest{
  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 discrimination parameters
  discr <- discrpar_grmtree(tree)
  print(discr)

# }