I'm recently learning how to design an ACBC conjoint study and learned that we can avoid bringing too many attributes in ACBC through a dynamic list, and the help document suggests that ideally, no more than 7 attributes should be brought to an ACBC exercise.
My question is when using this approach, do I need to have a consistent number of attributes to bring into ACBC? Or I can also set it as dynamic?
For example, if I have 9 attributes, and I'm going to bring 7 attributes into the ACBC. In my screening question, do I have to ask my respondents to pick up exactly 7 out of 9? Or I can ask them to pick up 5-7 attributes out of 9?
Therefore if some attribute is generally not selected by the respondents even before they get to the ACBC, we then know that these attributes are not appealing to them?