irt_assume: A function for checking the assumptions of IRT.

In Pflegermeister/wizirt: A United API for IRT

Description

This function checks the assumptions of IRT. For unidimensionality the DETECT, RATIO, and ASSI statistics are calculated using sirt::conf.detect(). For local dependence, the standardized LD statistic is calculated using mirt::residuals-method() and the correlations are created using ltm::rcor.test(). Relative fit calculates BIC, AIC, and several others using code from mirt::anova-method(). Absolute fit is calculated only for models run with the mirt engine, using mirt::M2(). See the documentation on those functions for more information on calculation.

Usage

irt_assume(wizirt_fit, verbose = FALSE)

Arguments

wizirt_fit	An object from fit_wizirt
verbose	Logical. Should the names of the other packages used in this function be printed? Default is FALSE.

Value

A list with tibbles of data in them.

Examples

data("responses")
my_model <- wizirt(data = responses[, -1])
assumptions <- irt_assume(my_model)
print(assumptions, type = "rel")
print(assumptions, type = "abs")
print(assumptions, type = "unid")
print(assumptions, type = "ld")

Pflegermeister/wizirt documentation built on Nov. 22, 2020, 8:27 p.m.