I am designing a CBC where the client wants every CBC screen to have 3 constant/fixed options. The remaining options on the CBC screen (beyond the 3 constant/fixed options) can vary per an experimental conjoint design as usually done with CBC.
The 3 constant/fixed options are competitive brand offerings. So there will be a "Brand" attribute with 10 brands/levels and 3 of these brands/levels will need to be shown on every single CBC screen.
I'm not sure how to implement this in LightHouse Studio but was planning to do an alternative specific design as follows:
(1) Every conjoint screen must show 10 options (that is, all 10 levels of the Brand attribute are shown on each screen - by using the complete enumeration or shortcut method and checking "Show Levels of First Attribute no more than Once per Task"). The None options will also be shown as an 11th option.
(2) The 10 level Brand attribute is the Primary attribute in the alternative specific design AND the 3 constant/fixed brand attribute levels have no (zero) attributes shown with them per the alternative specific design. BUT the 3 constant/fixed Brands will have a fixed/static visual text description shown to respondents using some of the same (and some different) attributes than those contained in the CBC design itself - the characteristics in the descriptions just won't be part of the conjoint experimental design (and will therefore not be part of the conjoint utilities/simulations that are done).
(3) Estimate utilities as usual in LightHouse Studio with default HB estimation to produce respondent level utilities.
So my questions are:
(1) Is it OK to design this CBC as explained above using this alternative specific design? Will it work OK statistically and produce HB respondent level utilities OR are there any major red flags?
(2) Is there a way to do this conjoint in LightHouse Studio using the built in design settings without showing all 10 brands on each screen (e.g., showing 5 brands on each screen with 3 fixed and 2 rotating per the experimental conjoint design) OR must all 10 brands be shown in order to be able to have 3 constant/fixed brands per screen?
Thank you.