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Two way probability of choice MBC

Hi,

In the MBC Manual i read:

MBC also reports two-way choice likelihoods of items (how often each combination of two levels was chosen).

If my questionnaire contains 5 menu choices

A
B
C
D
E

and i'm interested in the two-way choice likelihoods of A and B, are the reported two-way probabilities:

a) The combination of only A x B
OR
b) The combination of all possible ways of A x B occur together?
(A x B) + (A x B x C) + (A x B x D) ... (A x B x C x D x E)

I assume actual and expected likelihoods (for calculating synergy effects) are based on the same calculation?

Thanks
asked May 20, 2013 by anonymous

1 Answer

0 votes
MBC software will report all ways that A is combined with other items: 1-way, 2-ways, 3-ways, etc.

The manual talks about comparing actual joint likelihoods observed to expected joint likelihoods.  For example, if A and B separately have indendent likelihoods of 0.1 and 0.1, then the expected joint likelihood would be 0.1 x 0.1 = 0.01.  But, you can compare the expected likelihood to the actual joint likelihood as tabulated by the software.

The MBC software does not report expected joint probabilities, but only actual ones.  Expected joint probabilities you'd need to compute on your own.
answered May 20, 2013 by Bryan Orme Platinum Sawtooth Software, Inc. (134,015 points)
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