From groemping at bht-berlin.de  Mon Apr 26 22:36:13 2010
From: groemping at bht-berlin.de (=?ISO-8859-15?Q?Ulrike_Gr=F6mping?=)
Date: Mon, 26 Apr 2010 22:36:13 +0200
Subject: [Rd] Bug in calculation of overdispersion for quasibinomial
	grouped
Message-ID: <4BD5F93D.2050201@bht-berlin.de>

A quick addition:

SAS PROC LOGISTIC with option SCALE=PEARSON only calculates what R 
calculates in the grouped version; this is forced by refusing to 
calculate a FI estimate for ungrouped data, unless an AGGREGATE option 
is specified.

Apparently, SAS has decided for one model (not the one I am most 
familiar with), while the R version makes the model decision depend on 
the format of the data. As the family in glm is called quasibinomial, I 
would have expected it to conduct the adhoc adjustment.

Best, Ulrike

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* Ulrike Groemping                            *
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[Rd] Bug in calculation of overdispersion for quasibinomial grouped
=?ISO-8859-15?Q?Ulrike_Gr=F6mping?=