ITBiserial {exametrika} | R Documentation |
Item-Total Biserial Correlation
Description
The Item-Total Biserial Correlation computes the biserial correlation between each item and the total score. This function is applicable only to binary response data.
This correlation provides a measure of item discrimination, indicating how well each item distinguishes between high and low performing examinees.
Usage
ITBiserial(U, na = NULL, Z = NULL, w = NULL, ...)
Arguments
U |
U 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. |
Z |
Z is a missing indicator matrix of the type matrix or data.frame |
w |
w is item weight vector |
... |
Internal parameters for maintaining compatibility with the binary data processing system. Not intended for direct use. |
Value
A numeric vector of item-total biserial correlations. Values range from -1 to 1, where:
Values near 1: Strong positive discrimination
Values near 0: No discrimination
Negative values: Potential item problems
Note
This function is implemented using a binary data compatibility wrapper and will raise an error if used with polytomous data.
The biserial correlation is generally preferred over the point-biserial correlation when the dichotomization is artificial (i.e., when the underlying trait is continuous).
Examples
# using sample dataset
ITBiserial(J15S500)