fitP2G {lazy.irt}

R Documentation

Approximate Conversion of Graded Response Items to Partial Credit Items Using Logit Transformation

Description

Approximate Conversion of Graded Response Items to Partial Credit Items Using Logit Transformation

Usage

fitP2G(
  paramG,
  wtype = 1,
  DinP = 1,
  dataframe = 1,
  npoints = 21,
  thmin = -3,
  thmax = 3,
  maxabsv = 3,
  print = 1,
  plot = 0,
  debug = 0
)

Arguments

paramG	Item Parameter Data Frame for Graded Response Items
wtype	= 1 to use normal weight, else uniform
DinP	= 1 to include D=1.7 in logistic function
dataframe	= 1 to create parameter data frame, not matrix
npoints	# of discrete points for theta
thmin	Minimum value of discrete thata value
thmax	Maximum value of discrete thata value
maxabsv	Maximum absolute value of the weight
print	= 1 to print result
plot	= 1 to plot result
debug	= 1 to print intemediate result

Value

A list of: Partial Credit Model Item Parameter Data Frame in Nominal Format
Partial Credit Model Item Parameter Data Frame in Nominal Format0
Partial Credit Model Item Parameter Data Frame in Standard Format

Examples

paramP1 <- fitP2G( paramS1[3,], npoints=21, plot=1, print=1 )$paramP
paramG1 <- fitG2P( paramP1, npoints=21, plot=1, print=1 )

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