Hello!
I'm trying to do an orthogonal design for a choice experiment where the participants choose between 4 mobility alternatives. I want to fix one of the 4 alternatives as a status-quo for the individual but I don't know if it is correct to define a reference scenario in an orthogonal design? If it is possible, how to program it in my case? (I only find the answer for my question when using an efficient design)
The following is the preliminary design I'm using:
Design
;alts = Car, PT, Bicycle, Walking
;rows = 72
;orth = sim
;block=8
;model:
U(Car) = b1 + b2 * Time[-25,0,25] + b3 * Cost[-25,0,25] + b4 * Ind_mortality[0.7,0.8,0.9] + b5 * Coll_mortality[0.7,0.8,0.9] /
U(PT) = b2 * Time + b3 * Cost + b4 * Ind_mortality + b5 * Coll_mortality + b6 * Frequency[5, 10, 20]/
U(Bicycle) = b2 * Time+ b4 * Ind_mortality + b5 * Coll_mortality /
U(Walking) = b2 * Time+ b4 * Ind_mortality + b5 * Coll_mortality
$
Thank you in advance