Hi everyone

I am new in the forum. Hope one of you with expertise in choice experiments method can advice me.
My name is Poonyawee. I am using StataIC 16 for data analysis. I developed a questionnaire using choice experiments to estimate patients preference on osteoarthritis treatment. My attributes included pain relief, slow disease progression, gastrointestinal side effect, kidney side effect, cardiovascular side effect and cost of treatment. I ran MNL and this is my results.

mlogit y pain slow gi kid cv cost

Iteration 0: log likelihood = -1412.7494
Iteration 1: log likelihood = -1233.8452
Iteration 2: log likelihood = -1233.6762
Iteration 3: log likelihood = -1233.6762

Multinomial logistic regression Number of obs = 2,040
LR chi2(6) = 358.15
Prob > chi2 = 0.0000
Log likelihood = -1233.6762 Pseudo R2 = 0.1268

------------------------------------------------------------------------------
y | Coef. Std. Err. z P>|z| [95% Conf. Interval]
-------------+----------------------------------------------------------------
0 | (base outcome)
-------------+----------------------------------------------------------------
1 |
pain | .00819 .0029905 2.74 0.006 .0023287 .0140514
slow | .0129133 .0023527 5.49 0.000 .0083021 .0175244
gi | -.0127163 .0016884 -7.53 0.000 -.0160255 -.0094071
kid | -.0522486 .0046489 -11.24 0.000 -.0613604 -.0431369
cv | -.0542176 .0050274 -10.78 0.000 -.0640712 -.0443641
cost | -.0003448 .0000979 -3.52 0.000 -.0005367 -.0001529
_cons | 1.166027 .2011958 5.80 0.000 .7716902 1.560363
------------------------------------------------------------------------------

My problem is that I would like to know how to calculate mean and 95%CI of WTP. I try to use many syntax such as mixlogitwtp, nlcom but STATA show the error code. Please give me an advice.

Thank you in advance
Poonyawee