There's no particular reason why logistic regression could not be an adequate model. The issue is not whether the analysis can be actually DONE - it's how well the data FIT that type of model. When the probability of the event is very small, Poisson models often fit better than logistic models, that's all. Try both & see which fits better.

JW

On 15 May 01 23:01:44 GMT, bendiabare@NETSCAPE.NET (barrere Bendia) wrote:

>Hi there. > >I have data such that 2% of the event "dease= "1" > and 98% event "dease= "0" then proportion is p=2% and 1-p=98%. >I would make logistic regression with some Indep Vari: Var1, Var2, ... >Some variables are categorical other are continous. > >Some people say that I can't do logistic regression because the proportion p=2% is too small. But when I do it, It seems all things OK. There's convergence,and.. >CAN SOME ONE give any comment or justification ...? >Thank in advance. > >__________________________________________________________________ >Get your own FREE, personal Netscape Webmail account today at http://webmail.netscape.com/