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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
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