likelihoodKL | R Documentation |
Calculates the expected Kullback-Leibler information, weighted by likelihood, for a specified item.
likelihoodKL(catObj, item)
catObj |
An object of class |
item |
An integer indicating the index of the question item |
The function likelihoodKL
calculates the expected Kullback-Leibler information
for question item
, where the proposed values of the true ability parameter are weighted by
the current likelihood.
This function involves integration. See Note for more information.
The function likelihoodKL
returns a numeric indicating the
expected Kullback-Leibler information weighted by the likelihood
for the specified item, given the current answer profile and ability parameter estimate.
This function is to allow users to access the internal functions of the package. During item selection, all calculations are done in compiled C++
code.
This function uses adaptive quadrature methods from the GNU Scientific
Library (GSL) to approximate single-dimensional
integrals with high accuracy. The bounds of integration are determined by the
lowerBound
and upperBound
slots of the Cat
object.
Haley Acevedo, Ryden Butler, Josh W. Cutler, Matt Malis, Jacob M. Montgomery, Tom Wilkinson, Erin Rossiter, Min Hee Seo, Alex Weil
expectedKL
, posteriorKL
, selectItem
## Loading ltm Cat object data(ltm_cat) ## Store example answers setAnswers(ltm_cat) <- c(1,0,1,0,1, rep(NA, 35)) ## Estimate EPV for different unasked items likelihoodKL(ltm_cat, item = 10) likelihoodKL(ltm_cat, item = 20) likelihoodKL(ltm_cat, item = 30)
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