in my CBC analysis I want to find out what kind of impact Corporate Social Responsibility (CSR) has on a buyer's decision to choose an airline. I have five different attributes (Price, Seating Comfort, In-Flight Meals, Departure Time, and CSR). All attributes, except for CSR, will have three levels. Since I want to find out which CSR dimension (economic, social, ecological) has the biggest impact I would have 8 different levels if I want them to be mutually exclusive (all, none, econ., social, ecol., econ. & ecol., econ. & social, social & ecol.).
To avoid a number-of-levels effect I thought it would be best to transform this 8-level-attribute into three binary attributes (Economic Sustainability, Social Responsibility, and Ecological Responsibility).
Unfortunately I can only find technical papers regarding the number-of-levels effect but non that would strengthen my decision to use three binary attributes. My supervisor is worried that three binary attributes regarding CSR will also have a negative effect on the respondents because three out of seven attributes will be concerned with CSR.
It would really help to find a technical paper that confirms my decision. Any help would be highly appreciated.
Thank you very much.