PerFit.PFS {PerFit}

Compute several person-fit statistics

Description

Compute several person-fit statistics.

Usage

PerFit.PFS(matrix, method=NULL, simplified=TRUE, 
       NA.method = "Pairwise", Save.MatImp = FALSE,
       IP = NULL, IRT.PModel = NULL, Ability = NULL, Ability.PModel = NULL,
       mu = 0, sigma = 1)

Arguments

matrix

Data matrix of dichotomous item scores: Persons as rows, items as columns, item scores are either 0 or 1, missing values allowed.

method

Vector of person-fit statistics to be computed.

simplified

Logical. If FALSE, a list of PerFit objects is returned. If TRUE (default), a matrix with person-fit scores per respondent (one column per statistic) is reported.

NA.method

Method to deal with missing values. The default is pairwise elimination ("Pairwise"). Alternatively, simple imputation methods are also available. The options available are "Hotdeck", "NPModel" (default), and "PModel".

Save.MatImp

Logical. Save (imputted) data matrix to file? Default is FALSE.

IP

Matrix with previously estimated item parameters: One row per item, and three columns ([,1] item discrimination; [,2] item difficulty; [,3] lower-asymptote, also referred to as pseudo-guessing parameter).

In case no item parameters are available then IP=NULL.

IRT.PModel

Specify the IRT model to use in order to estimate the item parameters (only if IP=NULL).

Ability

Vector with previoulsy estimated latent ability parameters, one per respondent, following the order of the row index of matrix.

In case no ability parameters are available then Ability=NULL.

Ability.PModel

Specify the method to use in order to estimate the latent ability parameters (only if Ability=NULL).

mu

Mean of the apriori distribution. Only used when method="BM". Default is 0.

sigma

Standard deviation of the apriori distribution. Only used when method="BM". Default is 1.

Details

Function PerFit.PFS is a wrapper allowing to compute more than one person-fit statistic simultaneously.

Value

If simplified=TRUE, a N-by-m data frame is returned, where N is the number of respondents and m is the number of methods.

If simplified=FALSE a list of m PerFit objects is returned.

Author(s)

Jorge N. Tendeiro [e-mail]

Examples

# Load the inadequacy scale data (dichotomous item scores):
data(InadequacyData)

# Compute the lzstar, U3, and Ht scores:
PerFit.PFS(InadequacyData, method=c("lzstar", "U3", "Ht"))