各位老师,同学好。我现在做一个支付意愿的double hurdle模型,我分别用两种估计量来进行估计,但都跑不出来结果。求大神指教。
. dhreg wtp scogd sbeld partm a1 a2 a6 a9 b1 b7 j7 j10m ru72 l8m l13m
starting values for hurdle
Iteration 0: log likelihood = -1001.1827
Iteration 1: log likelihood = -887.34186
Iteration 2: log likelihood = -887.05872
Iteration 3: log likelihood = -887.05871
Probit regression Number of obs = 1,533
LR chi2(14) = 228.25
Prob > chi2 = 0.0000
Log likelihood = -887.05871 Pseudo R2 = 0.1140
__000002 Coef. Std. Err. z P>z [95% Conf. Interval]
scogd .0505657 .0694612 0.73 0.467 -.0855758 .1867072
sbeld .2041522 .07912 2.58 0.010 .0490799 .3592245
partm .2876747 .0627051 4.59 0.000 .1647749 .4105745
a1 .0111334 .0713991 0.16 0.876 -.1288063 .1510731
a2 -.0053861 .0029489 -1.83 0.068 -.0111658 .0003936
a6 .0037263 .010959 0.34 0.734 -.017753 .0252056
a9 .1311123 .0780339 1.68 0.093 -.0218313 .2840558
b1 -.0467042 .0211291 -2.21 0.027 -.0881166 -.0052919
b7 .0658806 .02333 2.82 0.005 .0201547 .1116065
j7 .1031676 .0288235 3.58 0.000 .0466745 .1596606
j10m .1495042 .0389519 3.84 0.000 .0731599 .2258486
ru72 -.2094405 .0901853 -2.32 0.020 -.3862004 -.0326806
l8m .1471619 .0376907 3.90 0.000 .0732895 .2210343
l13m .02279 .0448377 0.51 0.611 -.0650903 .1106702
_cons -1.640999 .3352383 -4.90 0.000 -2.298054 -.9839439
starting values conditional on hurdle being passed
Tobit regression Number of obs = 1,533
Uncensored = 982
Limits: lower = 0 Left-censored = 551
upper = +inf Right-censored = 0
LR chi2(14) = 249.15
Prob > chi2 = 0.0000
Log likelihood = -5612.9265 Pseudo R2 = 0.0217
wtp Coef. Std. Err. t P>t [95% Conf. Interval]
scogd 1.016141 2.836296 0.36 0.720 -4.54733 6.579611
sbeld 8.010264 3.371293 2.38 0.018 1.397382 14.62315
partm 11.94091 2.549542 4.68 0.000 6.939919 16.94191
a1 -3.538639 2.899082 -1.22 0.222 -9.225267 2.147989
a2 -.4615628 .1216089 -3.80 0.000 -.700102 -.2230236
a6 .2863734 .4559283 0.63 0.530 -.6079422 1.180689
a9 4.40715 3.103963 1.42 0.156 -1.681357 10.49566
b1 -2.118064 .8531194 -2.48 0.013 -3.79148 -.4446471
b7 5.305413 .8811812 6.02 0.000 3.576952 7.033874
j7 3.079113 1.147674 2.68 0.007 .8279189 5.330307
j10m 4.672899 1.652972 2.83 0.005 1.430551 7.915248
ru72 -8.358576 3.915525 -2.13 0.033 -16.03898 -.6781691
l8m 4.071926 1.635 2.49 0.013 .864828 7.279023
l13m .6336568 1.972329 0.32 0.748 -3.235119 4.502433
_cons -52.25508 14.14615 -3.69 0.000 -80.00313 -24.50702
/sigma 51.01697 1.197729 48.66759 53.36635
estimation assuming independence--------------------------------------------- ------ ----------- --------------
maximum likelihood estimates of double hurdle model
could not calculate numerical derivatives -- discontinuous region with missing values encountered
r(430);
end of do-file
r(430);
我看了一下,好像是最大似然估计,不能收敛。不知道应该怎么处理呢?求大神指导。感激不尽


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