ItemOdds {exametrika} | R Documentation |
Item Odds
Description
Item Odds are defined as the ratio of Correct Response Rate to Incorrect Response Rate:
O_j = \frac{p_j}{1-p_j}
where p_j
is the correct response rate for item j.
This function is applicable only to binary response data.
The odds value represents how many times more likely a correct response is compared to an incorrect response. For example, an odds of 2 means students are twice as likely to answer correctly as incorrectly.
Usage
ItemOdds(U, na = NULL, Z = NULL, w = NULL)
## Default S3 method:
ItemOdds(U, na = NULL, Z = NULL, w = NULL)
## S3 method for class 'binary'
ItemOdds(U, na = NULL, Z = NULL, w = NULL)
Arguments
U |
Either an object of class "exametrika" or raw data. When raw data is given,
it is converted to the exametrika class with the |
na |
Values to be treated as missing values. |
Z |
Missing indicator matrix of type matrix or data.frame. Values of 1 indicate observed responses, while 0 indicates missing data. |
w |
Item weight vector specifying the relative importance of each item. |
Value
A numeric vector of odds values for each item. Values range from 0 to infinity, where:
odds > 1: correct response more likely than incorrect
odds = 1: equally likely
odds < 1: incorrect response more likely than correct
Note
This function is implemented using a binary data compatibility wrapper and will raise an error if used with polytomous data.
Examples
# using sample dataset
ItemOdds(J5S10)