I will really appreciate any advice/suggestions here. I am a PhD student and for my research, I utilized a choice-based conjoint study designed in Lighthouse. I've already ran the experiment and collected the data.
But I'm having some doubts about my initial design (specifically whether or not there could be attraction effects in attribute levels, and whether or not they are truly independent).
Here is some context for my study. My research aims to investigate the impact of similarity of an individual (based on demographics and/or interests) and group size on decision making in the e-commerce context. To examine this, I used uncertainty-identity theory to propose a research model which I tested using an experimental procedure.
I decided to run the experiment with two separate parts. The first part was a two-way factorial between-subjects design. I adopted a 2 x 4 study to assess the main and interaction effects of two levels of group size and four levels of similarity on decision certainty. The design yielded eight experimental treatments, and fifty-two participants were randomly placed in each of these. The experiment consisted of a task after which respondents were administered a survey. The data was analyzed using partial least squares structural equation modelling.
The second experiment was a choice-based conjoint study/discrete choice experiment. Here, respondents were asked to go through 10 tasks each with 4 concepts and a none option. The attributes were similarity and group size, with 4 levels of similarity and 2 levels of group size (the same levels as in the first part of the experiment). I used a balanced overlap design approach.
The levels were as follows:
(1) No similarity
(2) Similarity in demographics
(3) Similarity in interests
(4) Similarity in both demographics and interests
(1) Small group size (10 people in the group)
(2) Large group size (150 people in the group)
I am concerned that perhaps the attribute levels for similarity are not mutually exclusive, because one of the levels is basically a combination of two other levels. And could there be attraction effects for the levels in group size? If this is the case, would be my data be unusable for the conjoint portion?
Here is a link to the study: https://resortbooker.sawtoothsoftware.com/login.html
Thank you for your help with this.