In my previous mail, meant to say "negative binomial regression" (not "negative poisson), of course. Dirk ************************************************* Dr. Dirk Enzmann Criminological Research Institute of Lower Saxony Luetzerodestr. 9 D-30161 Hannover Germany phone: +49-511-348.36.32 fax: +49-511-348.36.10 email: ENZMANN at KFN.uni-hannover.de http://www.kfn.de