ItemGPCM.data {pleLMA}

Creates data frame up-dating phi parameters of the gpcm.

Description

This function creates a data frame, 'gpcm.item.data', to be used in the item regressions of LMA models where category scales values are fixed. Sets up data for up-dating alpha parameters of the LMA that corresponds to the GPCM. This function is internal to 'item.gpcm' and it is unlikely to be run outside of 'fit.gpcm' or 'ple.lma'.

Usage

ItemGPCM.data(
  Master,
  ItemID,
  Phi.mat,
  TraitByTrait,
  pq.mat,
  starting.sv,
  npersons,
  nitems,
  ncat,
  nless,
  ntraits,
  LambdaName
)

Arguments

Master

Data frame of all data in long format

ItemID

Specifies the item for which a data frame is created to be input into an item regression

Phi.mat

Starting value of matrix of association parameters

TraitByTrait

Trait by trait adjacency matrix (same as inTraitAdj)

pq.mat

Array used to compute rest scores

starting.sv

Matrix of item category scores that are fixed

npersons

Number of persons

nitems

Number of items

ncat

Number of categories

nless

Number of unique lambdas (ncat-1)

ntraits

Number of latent traits

LambdaName

Names for lambda for item regression

Value

gpcm.item.data Data frame for item to be used up-dated in an item regression for specified item