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From: Wensui Liu on 1 Dec 2006 10:45 what tree algorithm are you using? I don't know how tree algorithm works in sas/ Eminer. but split method of some tree algorith doesn't depends on p-value at all, such as CART. My suggestion is to check the default setting of your program. A study indicates that analysis result is highly sensitive to the default setting of software, which is pretty interesting. On 11/29/06, amw5gster(a)gmail.com <amw5gster(a)gmail.com> wrote: > Howdy, > > Silly question that's likely to show I'm overlooking something simple, > but I'm stumped. I have a dset of approx 8M observations and I'm > trying to grow an EMiner decision tree on a binary target variable. > There are about 20 independent variables, mostly interval (dates), but > some nominal, a few binary and one ordinal. The proportion of true > events is about 12%. I have not set any prior probabilities, nor > profit/cost values. > > The tree runs, but returns no splits. It just won't grow. I've tried > dropping the signif value to .00001, using upwards of 11 maximum > branches and my max depth to 10. I also tried having the tree build on > as few as 2 IVs. > > I was able to build a tree when I took a sample of 100K records and > forced the %age of true events in the sample to be 50%. Naturally I > don't want to misrepresent the proportion, and I figured that 12% > wasn't terribly rare for a d-tree. > > Am I outright doing something wrong or is this expected behavior? > -- WenSui Liu (http://spaces.msn.com/statcompute/blog) Senior Decision Support Analyst Cincinnati Children Hospital Medical Center |