getItemDetails: Convenience function returning information about an...

In mixRasch: Mixture Rasch Models with JMLE

Description

This function extracts information about an individual item estimated using the mixRasch procedure.

Usage

getItemDetails(raschResult, item, class=1, camelCase=TRUE)

Arguments

raschResult	The result of a mixRasch analysis.
item	Either an integer representing the item position within the analysis or the item name (the column name from the dataframe used in the mixRasch analysis).
class	The class in a mixture Rasch analysis for which you want the item stats. In a standard Rasch analysis, class will always be 1.
camelCase	If TRUE, the variables returned are renamed to conform to camelCase style naming conventions.

Details

The function only requires a mixRasch result and an item number or name. If the analysis is a mixture analysis, the class from which the result is to be taken must be provided. The camelCase option is available so results can be exported to other software that might not supprt some types of R names (e.g., names with "."s in them).

Value

item.name	The name of the item.
n.cat	The number categories (e.g., 2 for dichotomous).
delta.i	Average step difficulty.
SE.delta.i	Standard error for delta.i.
tau	Step difficulty as a deviation from delta.i.
SE.tau	Standard error for tau.
infit	The infit statistic for the item
in.Z	The standardized infit statistic for the item
outfit	The outfit statistic for the item
out.Z	The standardized outfit statistic for the item
itemMean	The item mean, based on modal class.
pBis	The item-theta correlation, based on modal class.
bis	The item-theta polyserial correlation, based on modal class.

Author(s)

John T. Willse

Examples

# Example data included with mixRasch
data(SimMix)

test1 <- mixRasch(SimMix,1,50, conv.crit=.0001, n.c=1)
getItemDetails(test1,2)

mixRasch documentation built on May 2, 2019, 1:09 p.m.