ACBC Must-haves and Unacceptables

Question

In the ACBC design, we always see one more Unacceptable questions than Must-have questions, and the Unacceptable questions always come before the Must-haves.  Is there any particular reason that it is so?  Could we do more Must-have questions and fewer Unaccetables?  Or all many must-haves but no unacceptables?

Answer 1

You have lots of flexibility to do as many or as few Must Haves and Unacceptables (and in any order) as you desire.

Unacceptables are not as aggressive as Must Haves for potentially eliminating many levels at once as not a consideration for the respondent.  

For example, consider an attribute with six colors.  If the respondent says Purple is unacceptable, then this just eliminates one color from consideration.  But, if the respondent says they must have Blue, then that eliminates 5 colors all from that one mouse click.

We worry about respondents making decisions too early that would immediately knock out many levels at once as not possible for them.  That's why we chose to do things the way we did.  However, we are going more with what feels right rather than hard empirical evidence on this matter.

Comments

Great!  Exactly what we need to know.  Thanks again!

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I do wish that people can choose mutliple unaccetables and/or must haves in one shot.