dataFormat

This function serves the role of formatting the data prior to the analysis.

Usage

dataFormat(
  data,
  na = NULL,
  id = NULL,
  Z = NULL,
  w = NULL,
  response.type = NULL,
  CA = NULL
)

Arguments

data

is a data matrix of the type matrix or data.frame.

na

na argument specifies the numbers or characters to be treated as missing values.

id

id indicates the column number containing the examinee ID. If NULL (default), the first column is auto-detected as ID or response data. If a column number is specified, that column is always used as the ID column.

Z

Z is a missing indicator matrix of the type matrix or data.frame

w

w is item weight vector

response.type

Character string specifying the type of response data: "binary" for dichotomous data, "ordinal" for ordered polytomous data, "rated" for polytomous data with correct answers, "nominal" for unordered polytomous data. If NULL (default), the type is automatically detected.

CA

A numeric vector specifying the correct answers for rated polytomous data. Required when response.type is "rated".

Value

U

For binary response data. A matrix with rows representing the sample size and columns representing the number of items, where elements are either 0 or 1. \(u_{ij}=1\) indicates that student i correctly answered item j, while \(u_{ij}=0\) means that student i answered item j incorrectly.

Q

For polytomous response data. A matrix with rows representing the sample size and columns representing the number of items, where elements are non-negative integers. When input data is in factor format, the factor levels are converted to consecutive integers starting from 1.

ID

The ID label given by the designated column or function.

ItemLabel

The item names given by the provided column names or function.

Z

Missing indicator matrix. \(z_{ij}=1\) indicates that item j is presented to Student i, while \(z_{ij}=0\) indicates item j is NOT presented to Student i. If the data contains NA values, -1 is assigned.

w

Item weight vector

response.type

Character string indicating the type of response data: "binary", "ordinal", "rated", or "nominal"

CategoryLabel

List containing the original factor labels when polytomous responses are provided as factors. NULL if no factor data is present.

categories

Numeric vector containing the number of response categories for each item.

CA

For rated polytomous data, a numeric vector of correct answers. NULL for other types.