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How to field the CBC study with different number of concept in different tasks for the same respondents


How to field the CBC study with different number of concept in different tasks for the same respondents

I would like to vary the number of concepts presented (available) in different choice task for the same respondent in order to evaluate the potential of introducing specific promotion together with regular offer.
Is there any way to make CBC accept different number of concepts per choice task?

Best regards,

asked Nov 28, 2018 by RafalNeska (450 points)

1 Answer

+1 vote

You would have to "trick" our software into doing this, followed up by some manual data processing on your part.  The trick is to program two different CBC exercises that have exactly the same attributes and levels, but only differ in terms of how many product concepts are shown per screen.  Then, you move around the choice tasks in the question list (using the up and down arrows under Write Questionnaire) so that the two CBC exercises are mixed together (for example... Exercise1Task1, Exercise2Task1, Exercise1Task2, Exercise2Task2, etc.)

For analysis (assuming you'll be doing either Latent Class or HB estimation), you would need to export both CBC exercises to either .CHO format or the easier "Single Format .CSV" file.  Then, you need to combine the files you exported so that you gather all the choice tasks (from the different exercises) within each respondent.  You will need to use the standalone Latent Class or standalone CBC/HB software programs to estimate the utilities, because Lighthouse Studio cannot accept this combined data file.
answered Nov 28, 2018 by Bryan Orme Platinum Sawtooth Software, Inc. (174,440 points)
Thank you for your advice.
I will need more than 2 versions (there will probably be more than 10 promo skus that are to be either available or unavailable).
I wonder if there is any other solution:).
Best regards, Rafał
The solution I described can handle as many versions as you want to do.  I just gave the example with 2 versions to keep it more simple.