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Dear Dr. Jay: Discrete Choice—How Many Is Too Many Features?

Posted by Dr. Jay Weiner on Wed, Mar 23, 2016

Dear Dr. Jay,

I’m interested in testing a large number of features for inclusion in the next version of my product. My team is suggesting that we need to cull the list down to a smaller set of items to run a choice model. Are there ways to test a large set of attributes in a choice model?


 DRJAY.pngHi Nick –

There are a number of ways to test a large set of attributes in choice modeling. Most of the time, when we test a large number of features, many are simply binary attributes (included/not included). While this makes the experimental design larger, it’s not quite as bad as having ten six-level attributes. If the description is short enough, you might go ahead and just include all of them. If you’re concerned about how much reading a respondent will need to do—or you really wouldn’t offer a respondent 12 additional perks for choosing your credit card—you could put a cap on the number of additional features any specific offer includes. For example, you could test 15 new features in a single model, but respondents would only get up to 5 at any single time. This is actually better than using a partial profile design as all respondents would see all offers. 

Another option is to do some sort of bridging study where you test all of the features using a max diff task. You can include a subset of the factors in a DCM and then use the max diff utilities to compute the utility for the full list of features in the DCM. This allows you to include the full set of features in your simulation tool.

Dr. Jay loves designing really big, complex choice models.  With over 20 years of DCM experience, he’s never met a design challenge he couldn’t solve. 

Topics: advanced analytics, product development, Dear Dr. Jay