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In Excel-based simulators from MBC projects, can we add/remove products?

In SMRT and the online simulator, we can add/remove as many products as desired. In MBC projects in which the products presented were experimentally designed, can we do the same in the resulting Excel-based simulator?
asked Aug 18, 2013 by anonymous
I did for simple CBC excel based simulator lot of time, I hope this can be done for MBC exercise as well.

1 Answer

0 votes
Most of the time, when using MBC, the menu is considered a whole where all items are present.  Thus, the simulator produces predictions for all items on the menu.

But, if you experimentally designed the MBC menu to have products that sometimes appear and sometimes disappear, then you should also have computed an "availability term" that signals to the utility estimation routine (as a dummy code) when an item is removed from the menu.  When you set that "availability flag" within the simulator (just another independent variable) to indicate that the product was not available, its share should be driven to nearly (almost exactly) zero.

However, my guess is you haven't done that.  My guess is you want to drop an alternative from the menu and have the remaining share for the other product alternatives sum to 100% (which is something that respondents never actually saw in the survey).  If that's the case, then I don't think our Excel-based simulator that the MBC software produces can automatically do that.   So, you'd need to do some modification to the Excel simulator so that the individual respondent shares of preference for the dropped product alternative are set to zero and the other items are shown to capture the full 100% of share.  This makes a simplifying assumption, however, that the remaining products in the market simulator take up share in an "IIA" manner, proportional to their previous shares (it assumes constant substitution rates).
answered Aug 20, 2013 by Bryan Orme Platinum Sawtooth Software, Inc. (131,990 points)
Hi Bryan,

Actually, I haven't done anything yet - I'm just thinking ahead of future projects.

I'm thinking of an MBC exercise similar to the one you show in figure 1.9 of the MBC booklet (page 9 here https://www.sawtoothsoftware.com/download/mbcbooklet.pdf ). In that exercise we're showing 3 different products with varying characteristics. Does this mean that the Excel simulator resulting from this particular example can only show market simulations with 3 products? It sounds like I'd need to create a different Excel simulation file for all the different possible number of products the client may want in the simulation scenario, or add some kind of check box to enable/disable the presence of a product.