Stata学习：如何构建支付意愿空间混合logit模型？

set seed 537363959
mixlogitwtp outcome if validated==1,  rand(goodexperiencebiogas_ifbg badexperiencebiogas_ifbg noexperiencebiogas_ifbg alternisrocket maint_higher smoke_lower fuelefficiency) price(negprice) id(id) group(case) 
estimates store MXL_exp
estimates restore MXL_exp
mixlbeta goodexperiencebiogas_ifbg badexperiencebiogas_ifbg noexperiencebiogas_ifbg alternisrocket maint_higher smoke_lower fuelefficiency, nrep(1000) saving(wtpexp_distribution) replace

Iteration 0:  Log likelihood = -1551.5136  (not concave)
Iteration 1:  Log likelihood = -1544.5129  (not concave)
Iteration 2:  Log likelihood = -1481.3067  (not concave)
Iteration 3:  Log likelihood = -1461.4711  (not concave)
Iteration 4:  Log likelihood = -1440.4676  (not concave)
Iteration 5:  Log likelihood = -1355.3401  (not concave)
Iteration 6:  Log likelihood = -1328.5785  
Iteration 7:  Log likelihood =    -1316.8  (not concave)
Iteration 8:  Log likelihood = -1315.2515  (not concave)
Iteration 9:  Log likelihood = -1314.0268  
Iteration 10: Log likelihood =  -1313.016  
Iteration 11: Log likelihood = -1312.8286  (not concave)
Iteration 12: Log likelihood = -1311.9755  
Iteration 13: Log likelihood = -1311.7381  
Iteration 14: Log likelihood = -1311.7282  
Iteration 15: Log likelihood = -1311.7282  

Mixed logit model in WTP space                         Number of obs =   5,484
                                                       Wald chi2(8)  = 4090.87
Log likelihood = -1311.7282                            Prob > chi2   =  0.0000

-------------------------------------------------------------------------------------------
                  outcome | Coefficient  Std. err.      z    P>|z|     [95% conf. interval]
--------------------------+----------------------------------------------------------------
Mean                      |
goodexperiencebiogas_ifbg |   7348.172   596.1974    12.33   0.000     6179.646    8516.697
 badexperiencebiogas_ifbg |   5743.991    525.265    10.94   0.000      4714.49    6773.491
  noexperiencebiogas_ifbg |   2836.663   800.9085     3.54   0.000     1266.911    4406.415
           alternisrocket |  -2768.394   918.7587    -3.01   0.003    -4569.128   -967.6605
             maint_higher |   608.8961   404.4207     1.51   0.132    -183.7539    1401.546
              smoke_lower |   4784.997   456.2536    10.49   0.000     3890.757    5679.238
           fuelefficiency |   3074.038   320.1424     9.60   0.000      2446.57    3701.505
                 negprice |  -7.587495    .144576   -52.48   0.000    -7.870858   -7.304131
--------------------------+----------------------------------------------------------------
SD                        |
goodexperiencebiogas_ifbg |   5654.514   831.5416     6.80   0.000     4024.723    7284.306
 badexperiencebiogas_ifbg |   4184.776   558.7539     7.49   0.000     3089.639    5279.914
  noexperiencebiogas_ifbg |  -6880.632   763.6405    -9.01   0.000    -8377.339   -5383.924
           alternisrocket |  -6146.829   654.2155    -9.40   0.000    -7429.068    -4864.59
             maint_higher |  -3213.146   591.0612    -5.44   0.000    -4371.604   -2054.687
              smoke_lower |   1388.787   384.9297     3.61   0.000     634.3389    2143.236
           fuelefficiency |  -520.4972   379.1623    -1.37   0.170    -1263.642    222.6472
                 negprice |   .7824771   .1572334     4.98   0.000     .4743053    1.090649
-------------------------------------------------------------------------------------------
The sign of the estimated standard deviations is irrelevant: interpret them as
being positive

. estimates store MXL_exp

. estimates restore MXL_exp
(results MXL_exp are active now)

. mixlbeta goodexperiencebiogas_ifbg badexperiencebiogas_ifbg noexperiencebiogas_ifbg alternisrocket ma
> int_higher smoke_lower fuelefficiency, nrep(1000) saving(wtpexp_distribution) replace
(file wtpexp_distribution.dta not found)
file wtpexp_distribution.dta saved