Predictive model for rare event

Posted by Paul-2 on Jul 30, 2011; 12:09pm
URL: http://spssx-discussion.165.s1.nabble.com/Predictive-model-for-rare-event-tp4649637.html

Hi everyone,

I would like to build a predictive model(Logistic regression or decision
tree or NNet . But the frequency of the event I am predicting is extremely
small less than 1%.
In fact here is my frequency distribution of my dependent variable
Churn_ind
Churn_ind=1  150(0.75%)
Churn_ind=0  19850(99.25%).
Questions:
Q1: What is the minimum sample size to run a reliable model?
Q2: What model could best fit this type of distribution where my event is
less than 1% and in this case 150 out of 20000 ?
Q3:Is there a minimum N sample size when running a decision Tree I tried
to run a decision but got no results.
I turning to the group here to seek for ideas . Your assistance is more
more than welcome.

Thanks,

Paul

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