Another recent article from Discovery Corps, Inc. president Tim Graettinger:   Grab Bag 2:  More Frequently-Asked Questions about Data Mining.  

"While helping present a monthly webinar on Data Mining, I'm asked some challenging and really pivotal questions about DM and predictive analytics:  

1. How much data do I need? 
2. Why doesn't my predictive model perform as well on new data as it did on the training data?
3. Are new DM algorithms needed to produce better results? 

Here are the answers I've learned....   Read Grab Bag 2 article