read.param {lazy.irt}R Documentation

Reading Parameter File

Description

Reading Parameter File

Usage

read.param(infile, skip = 0, nrows = -1, na.strings = "NA", sep = "",
  print = 0)

Arguments

infile

Input file name

skip

# of lies to skip

nrows

NOT used

na.strings

A character indicating missing value

sep

Delimite character

print

= 1 to print result

Details

It is assumed that the data file has the following quantities in the following order.

item_name, item_type, ncat, p1, p2, ..., p[ncat+1]

The first line must consist of the variable names shown above.
If the data file has header lines berore variable names, those lines must be skipped by specifying skip= parameter.
When item_type == "B", ( ncat == 2 )
p1 is the discrimination parameter
p2 is the difficulty parameter
p3 is the gussing parameter

When item_type == "G",
p1 is the discrimination parameter
p2 is the category threshold parameter b_j1
p3 is the category threshold parameter b_j2

p_ncat is the category threshold parameter b_j,[ncat-1]

When item_type == "P",
p1 is the discrimination parameter
p2 is the step parameter b_j1
p3 is the step parameter b_j2

p_ncat is the step parameter b_j,[ncat-1]

When item_type == "PN,
p1 is the slope parameter
p2 is the intercept parameter b_j1
p3 is the intercept parameter b_j2

p_ncat is the intercept parameter b_j,[ncat-1]

When item_type == "N,
p1 - p_(ncat[j]-1) are the slope parameters
p_ncat[j] - p_2*(ncat[j]-1) are the intercept parameters

Regardless of the item_type, there will be ncat[j]
item paramters for item j, except for the Binary Items
which have the gusseing param as the ncat[j]+1st,
and the Nominal Items which have 2*(ncat[j]-1) item parameters.


[Package lazy.irt version 0.1.3 Index]