Candy Calculation?

Lundgren has published at length on Return On Investment when considering package liquor, beer and transportation and I believe I recently saw some discussion on variables to consider when putting a Halloween costume together. Has anybody come up with an algorithm, equation or model for predicting how much Halloween candy to stage for distribution? Last year, I had to recycle the stuff the kids brought home and based this year’s purchase off that. Now we are stuck with seven pounds of Reese’s [at least we predicted there would be left overs]. Anybody identified trends or tricks used with this annual purchase?