\name{Gleser}
\alias{Gleser}
\docType{data}
\title{
Example data from Gleser, Cronbach and Rajaratnam (1965) to show basic principles of generalizability theory. 
}
\description{
Gleser, Cronbach and Rajaratnam (1965) discuss the estimation of variance components and their ratios as part of their introduction to generalizability theory.  This is a adaptation of their "illustrative data for a completely matched G study" (Table 3).  12 patients are rated on 6 symptoms by two judges.  Components of variance are derived from the ANOVA. 
}

\usage{data(Gleser)}
\format{
  A data frame with 12 observations on the following 12 variables. J item by judge:
  \describe{
    \item{\code{J11}}{a numeric vector}
    \item{\code{J12}}{a numeric vector}
    \item{\code{J21}}{a numeric vector}
    \item{\code{J22}}{a numeric vector}
    \item{\code{J31}}{a numeric vector}
    \item{\code{J32}}{a numeric vector}
    \item{\code{J41}}{a numeric vector}
    \item{\code{J42}}{a numeric vector}
    \item{\code{J51}}{a numeric vector}
    \item{\code{J52}}{a numeric vector}
    \item{\code{J61}}{a numeric vector}
    \item{\code{J62}}{a numeric vector}
  }
}
\details{
Generalizability theory is the application of a components of variance approach to the analysis of reliability.  Given a G study (generalizability) the components are estimated and then may be used in a D study (Decision).  Different ratios are formed as appropriate for the particular D study.
}
\source{
Gleser, G., Cronbach, L., and Rajaratnam, N. (1965). Generalizability of scores influenced by multiple sources of variance. Psychometrika, 30(4):395-418. (Table 3, rearranged to show increasing patient severity and increasing item severity.

}
\references{
Gleser, G., Cronbach, L., and Rajaratnam, N. (1965). Generalizability of scores influenced by multiple sources of variance. Psychometrika, 30(4):395-418.
}
\examples{
#Find the MS for each component:
#First, stack the data
data(Gleser)
stack.g <- stack(Gleser)
st.gc.df <- data.frame(stack.g,Persons=rep(letters[1:12],12),
Items=rep(letters[1:6],each=24),Judges=rep(letters[1:2],each=12))
#now do the ANOVA
anov <- aov(values ~ (Persons*Judges*Items),data=st.gc.df)
summary(anov)
}
\keyword{datasets}