I would like to do recursive partitioning when the response is a
  count variable subject to overdispersion, using say negative 
  binomial likelihood or something like quasipoisson in glm.  Would 
  appreciate any thoughts on how to go about this (theory/computation).
  If I understand the rpart documentation, I would need to write a 
  method argument, but the details are not there.  Therefore, a second
  question is whether/where one can get material on developing new
  rpart implementations. 
   
  regards,
  Farrar

	[[alternative HTML version deleted]]

