summary.rasch {ltm}R Documentation

Summary method for rasch objects

Description

Summarizes the fit of a rasch object.

Usage

## S3 method for class 'rasch':
summary(object, robust.se = FALSE, ...)

Arguments

object an object inheriting from class rasch.
robust.se logical; if TRUE robust estimation of standard errors is used, based on the sandwich estimator.
... additional argument; currently none is used.

Value

An object of class summ.rasch with components,

coefficients the estimated coefficients' table.
Var.betas the approximate covariance matrix for the estimated parameters.
logLik the log-likelihood of object.
AIC the AIC for object.
BIC the BIC for object.
max.sc the maximum absolute value of the score vector at convergence.
conv the convergence identifier returned by optim.
counts the counts argument returned by optim.
call the matched call of object.
control the values used in the control argument in the fit of obj.
nitems the number of items in the data set.

Note

For the parameters that have been constrained, the standard errors and z-values are printed as NA.

Author(s)

Dimitris Rizopoulos dimitris.rizopoulos@med.kuleuven.be

See Also

rasch

Examples


## The Rasch model for the Wirs data:
m <- rasch(Wirs)
summary(m)

## The Rasch model for the Lsat data:
m <- rasch(Lsat, constraint = rbind(c(6,1)))
summary(m)

## The Rasch model for the Abortion data:
m <- rasch(Abortion)
summary(m, TRUE)


[Package ltm version 0.2-1 Index]