\encoding{UTF-8}
\name{Thurstone}
\docType{data}
\alias{Thurstone}
\alias{box20}
\alias{box26}
\title{Thurstone Box Data}
\description{
  Factor loading matrices derived from Thurstone's box data, a classic
  dataset in factor analysis consisting of measurements of physical
  dimensions of a set of boxes.
}
\usage{
  data(Thurstone)
}
\details{
  Loading the data makes two objects available:

  \code{box26} is a \eqn{26 \times 3}{26 x 3} unrotated factor loading
  matrix for 26 variables measured on a set of boxes. This is the
  recommended matrix for use in examples and benchmarking. It appears
  frequently in the rotation literature as a benchmark dataset for
  comparing rotation criteria, particularly for assessing local minima.

  \code{box20} is a \eqn{20 \times 3}{20 x 3} unrotated factor loading
  matrix for 20 variables measured on the same set of boxes.
  \strong{Deprecated:} \code{box20} will be removed in a future version
  of \code{GPArotation}. Use \code{box26} instead.

  Both matrices are suitable as input to \code{GPForth}, \code{GPFoblq},
  and all rotation wrapper functions in \code{GPArotation}. For a richer
  collection of factor analysis datasets, see the \code{psych} package.
}
\format{
  Two numeric matrices:
  \itemize{
    \item \code{box26}: 26 x 3 matrix of unrotated factor loadings
          (recommended).
    \item \code{box20}: 20 x 3 matrix of unrotated factor loadings
          (deprecated; use \code{box26} instead).
  }
}
\source{
  Thurstone, L.L. (1947). \emph{Multiple Factor Analysis}.
  University of Chicago Press.
}
\seealso{
  \code{\link{GPForth}},
  \code{\link{rotations}},
  \code{\link{Harman}},
  \code{\link{CCAI}},
  \code{\link{WansbeekMeijer}}
}
\keyword{datasets}