\HeaderA{glm.convert}{Change a Negative Binomial fit to a GLM fit}{glm.convert}
\keyword{regression}{glm.convert}
\keyword{models}{glm.convert}
\begin{Description}\relax
This function modifies an output object from \code{glm.nb()} to one
that looks like the output from \code{glm()} with a negative binomial
family.  This allows it to be updated keeping the theta parameter
fixed.
\end{Description}
\begin{Usage}
\begin{verbatim}
glm.convert(object)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{object}] An object of class \code{"negbin"}, typically the output from
\code{\LinkA{glm.nb}{glm.nb}()}.

\end{ldescription}
\end{Arguments}
\begin{Details}\relax
Convenience function needed to effect some low level changes to the
structure of the fitted model object.
\end{Details}
\begin{Value}
An object of class \code{"glm"} with negative binomial family.  The theta
parameter is then fixed at its present estimate.
\end{Value}
\begin{SeeAlso}\relax
\code{\LinkA{glm.nb}{glm.nb}}, \code{\LinkA{negative.binomial}{negative.binomial}}, \code{\LinkA{glm}{glm}}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
quine.nb1 <- glm.nb(Days ~ Sex/(Age + Eth*Lrn), data = quine)
quine.nbA <- glm.convert(quine.nb1)
quine.nbB <- update(quine.nb1, . ~ . + Sex:Age:Lrn)
anova(quine.nbA, quine.nbB)
\end{ExampleCode}
\end{Examples}

