I am a new user of Ngene and this is my first DCE. I am working on a labeled DCE to estimate WTPs for repairing household appliances.
I have 4 alternatives : DIY repair, Pro repair, Replace with new, and opt-out option.
I have already done the first design, and the pilot study. So I want to add the priors I got from my mnl estimation in stata. However, I have a few questions :
- Are the priors the same for all alternatives ? means if the beta coefficient for attribute cost is 0.3, do I use the same prior for all of my three alternatives ?
- Concerning the ASC, I know that it is better to add them.. I did not in the pilot study design however. If I understood well from my readings on this forum, I can add ASC to only three of the four alternatives I have. So the prior for the ASC is what in this case ? In the database collected from the pilot study I have added dummy coded variables for each alternative... do I use this coefficient as a prior ?
- Do I need to take other things into consideration ?
-
- Code: Select all
design
;alts = DIY*, PRO*, Replace*, neither
;rows = 24
;block = 3
; eff = (mnl, d)
;cond:
if(DIY.cost1=10, PRO.cost2=[50,85]),
if(DIY.cost1=40, PRO.cost2=[85,120,200]),
if(DIY.cost1=70, PRO.cost2=[120,200]),
if(DIY.cost1=150, PRO.cost2=[200]),
if(PRO.cost2=50, PRO.bonus=[15]),
if(PRO.cost2=120, PRO.bonus=[15,30])
;model :
U(DIY) = DIY[0]
+ b1.dummy[0.2]*tutorial [1,0]
+ b2[-0.00149]*cost1 [10,40,70,150]
+ b4[-0.0344]*CO2 [10,20]
+ b5[-0.03]*duration1 [3,7,15]/
U(PRO)= PRO[0]
+ b2[-0.00149]*cost2 [50,85,120,200]
+ b3[0.00001]*bonus [15,30]
+ b4[-0.0344]*CO2 [10,20]
+ b5[-0.03]*duration2 [1,3,7,15]
+ b6[0.0592]*warranty1 [3,6,12]/
U(Replace) = b2[-0.00149]*cost3 [300,400,500]
+ b4[-0.0344]*CO2 [10,20]
+ b5[-0.03]*duration3 [3,7]
+ b6[0.0592]*warranty2 [24]/
U(neither) = neither[0]
$