- In my CBC, I have n = 220 and 10 pair-wise comparisons, i.e., each respondent evaluates 20 choice options in 10 choice tasks. Each choice options has 5 attributes รก 3 levels.

- In my pre-study, I used a d-optimal fractional design generated, i.e., each respondent saw the same 20 options.

- In my main study, my survey tool was accidentally set to random design, i.e., each respondent saw 20 randomly generated options.

I am not sure if there problems associated with a random design - at least all CBC articles I came across use fixed designs.

Could you help me out here, as I need to decide whether I can proceed working with the conjoint data obtained from random design, or whether I should repeat the study with a fixed design.

Many thanks for your help!

So just to make sure: Basically each of the 220 respondents had a different, random set of 10 pair-wise comparisons with randomly generated choice options (not: a purely randomly generated set of 20 choice options that was the same for all respondents).

But there is no problem in that? (I am just investigating main effects)

Again, thanks for your help!