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How to do an MBC allowing multiple purchases of individual products

We are currently looking at the best way to set up an MBC survey.  The design is relatively simple - multiple expressions of three different products with associated prices.  On each screen we wish to show one of the options of each product and allow for each of the products to be selected, however, we would also like for each of the products to be selected a number of times - i.e. a number to be inputted next to each product.  Although the actual design of the survey to incorporate this will not be too difficult i would appreciate advice on how we would analyse such data within MBC.
asked Mar 6, 2015 by N Game

1 Answer

0 votes
This sounds to me like the classic "Volumetric CBC" approach: show multiple products on the screen and ask respondents to allocate purchase volume to the concepts (where the purchase volume is not held constant per task).

MBC software will not do this.  It requires a bit of customized analysis beyond CBC.  You may use our CBC software to design, field, and collect such volumetric CBC data.

But, the analysis of the Volumetric CBC data is not automatically supported by our CBC software.  You need to do some extra stuff on the back end.  There are two models that I can remember off the top of my head that are sometimes done by our users:

1.  "None picks up the slack" approach.  This is the easier method and is described at: http://www.sawtoothsoftware.com/help/issues/ssiweb/online_help/hid_web_volumetriccbc.htm

2.  Two-step logit + regression approach (trickier than option 1).  See Tom Eagle's 2010 Sawtooth Software Conference paper at: http://www.sawtoothsoftware.com/support/technical-papers/conference-proceedings/proceedings2010
answered Mar 6, 2015 by Bryan Orme Platinum Sawtooth Software, Inc. (128,265 points)
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