if (FALSE) {
mod <- mirt(Science, 1)
coef(mod, simplify=TRUE, IRTpars = TRUE)$items
gen.difficulty(mod)
gen.difficulty(mod, type = 'mean')
# also works for dichotomous items (though this is unnecessary)
dat <- expand.table(LSAT7)
mod <- mirt(dat, 1)
coef(mod, simplify=TRUE, IRTpars = TRUE)$items
gen.difficulty(mod)
gen.difficulty(mod, type = 'mean')
}
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