scoreCon: Function to create a score conversion table from Rasch item...
In wasabi1989/MiscPsycho: Miscellaneous Psychometric Analyses

Description Usage Arguments Value Note Author(s) Examples

Creates a score conversion table using the estimated item parameters

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scoreCon(b_vector)
## Default S3 method:
scoreCon(b_vector)

b_vector

vector of estimated item parameters

A list with class "scoreCon" containing the following components:

`Estimate`	the maximum likelihood estimate (MLE, or ability estimate) conditional on the item parameters
`Std.Error`	the estimated standard error of the ability estimate
`Raw.Score`	the associated raw test score. Since Rasch does not use pattern scoring, all raw scores have the same MLE.

Scores cannot be provided for individuals with 0 correct or all incorrect because the likelihood function is unbounded in these cases. Other scoring methods, such as the EAP or MAP are available for these scenarios. See irt.ability for more general scoring methods

Harold Doran

set.seed(1234)
tmp <- data.frame(item1 = sample(c(0,1), 20, replace=TRUE), item2 = sample(c(0,1), 20, replace=TRUE),
item3 = sample(c(0,1), 20, replace=TRUE),item4 = sample(c(0,1), 20, replace=TRUE),item5 = sample(c(0,1), 20, replace=TRUE))

## Estimate item parameters from JML (or provide them as a numeric vector)
fm1 <- jml(~ item1 + item2 + item3 + item4 + item5, data = tmp)
summary(scoreCon(coef(fm1)))