% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/plots.R
\name{plot_pca}
\alias{plot_pca}
\title{Plot residual principal-component loadings}
\usage{
plot_pca(fit, component = 1)
}
\arguments{
\item{fit}{A fitted object from \code{\link{rasch}}.}

\item{component}{Which residual principal component to plot (default the
first component).}
}
\value{
Called for its plotting side effect; invisibly \code{NULL}.
}
\description{
Residual-component loadings against item location; opposing clusters at top
and bottom suggest a further dimension. Any leading component may be shown,
not only the first.
}
\examples{
set.seed(1)
d <- seq(-2, 2, length.out = 6)
X <- matrix(rbinom(400 * 6, 1, plogis(outer(rnorm(400), d, "-"))), 400, 6)
colnames(X) <- paste0("I", 1:6)
plot_pca(rasch(X))
}
