. xtfrontier lny lnk lnl lne u v w kl ke le,tvd
Iteration 0: log likelihood = -264.8483 (not concave)
Iteration 1: log likelihood = -103.39249 (not concave)
Iteration 2: log likelihood = 62.627285 (not concave)
Iteration 3: log likelihood = 94.522881 (not concave)
Iteration 4: log likelihood = 109.86619 (not concave)
Iteration 5: log likelihood = 140.50746 (not concave)
Iteration 6: log likelihood = 169.13184 (not concave)
Iteration 7: log likelihood = 188.80884
Iteration 8: log likelihood = 218.4021
Iteration 9: log likelihood = 224.20939
Iteration 10: log likelihood = 225.18014
Iteration 11: log likelihood = 225.82945
Iteration 12: log likelihood = 226.01226
Iteration 13: log likelihood = 226.02161
Iteration 14: log likelihood = 226.02163
Time-varying decay inefficiency model Number of obs = 336
Group variable: indt Number of groups = 24
Time variable: year Obs per group:
min = 14
avg = 14
max = 14
Wald chi2(9) = 945.26
Log likelihood = 226.02163 Prob > chi2 = 0.0000
lny Coef. Std. Err. z P>z [95% Conf. Interval]
lnk .710347 .3264166 2.18 0.030 .0705822 1.350112
lnl -2.553844 .3435434 -7.43 0.000 -3.227176 -1.880511
lne .5677815 .2738052 2.07 0.038 .0311331 1.10443
u -.4420403 .0768785 -5.75 0.000 -.5927193 -.2913612
v -.2140786 .0802215 -2.67 0.008 -.3713099 -.0568474
w -.1956239 .0492786 -3.97 0.000 -.292208 -.0990397
kl .3838759 .0709003 5.41 0.000 .2449139 .522838
ke .0662752 .0515311 1.29 0.198 -.0347238 .1672743
le .1143363 .048866 2.34 0.019 .0185608 .2101119
_cons 10.74318 1.193508 9.00 0.000 8.403947 13.08241
/mu .9688291 .2159159 4.49 0.000 .5456416 1.392017
/eta .0495754 .0068532 7.23 0.000 .0361434 .0630074
/lnsigma2 -1.857175 .3592555 -5.17 0.000 -2.561303 -1.153047
/lgtgamma 2.688984 .3984041 6.75 0.000 1.908126 3.469842
sigma2 .1561131 .0560845 .0772041 .3156734
gamma .9363735 .0237362 .8708085 .9698174
sigma_u2 .1461801 .0561396 .0361486 .2562117
sigma_v2 .0099329 .0008029 .0083593 .0115066
lnl的系数为负数,好像解释不了啊。并且出现负值后求要素的产出弹性便也会是负值。。。请教各位大佬,论坛币不多了,30个不成敬意。谢谢!