Hi Choice Metrics Team,
I am trying to generate a design for a freight mode choice survey and therefore need to use a labeled alternative specific design.
I included priors based on studies but I’m planning to do a pilot study to confirm the assumptions. Here is the current design:
design
;alts = A,B,C
;rows = 32
;block = 4
;eff = (mnl,d)
;model:
U(A) = b1[-0.0051] * RateA[4400,4900,5600]+ b2[0.0245]* FrequA[7,10,15] + b3[-0.0325] * TimeA[19,24,36] + b4[0.0457] * ReliaA[1,5] /
U(B) = b1 * RateB[1100,1300,1500] + b2 * FrequB[2,5,6]+ b3 * TimeB[30,36,48]+ b4 * ReliaB[0,3] /
U(C) = b1 * RateC[2700,3000,3300]+ b2 * FrequC[2,5,8]+ b3 * TimeC[48,60,72] +b4 * ReliaC[2,4]
$
MNL efficiency measures are: D-error: 0.110073, A-error: 2.683779, B-estimate: 2E-06, S-estimate: 15361.698928. There is obviously something wrong with this design. I tested it with slightly different attribute levels and priors but could not generate a major improvement on the efficiency of the design.
I would be very grateful for any comments on the design.
Cheers,
Pauline