auirzxp 发表于 2015-3-17 10:53 
必须同时满足AR(不一定AR2,有可能AR2显著,而AR3不显著,在这种情况下用三阶滞后)和sargan(或者Hanse ...
您帮我看看这个结果,还是一阶滞后的工具变量
Dynamic panel-data estimation, one-step system GMM
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Group variable: industry Number of obs = 14022
Time variable : t Number of groups = 114
Number of instruments = 125 Obs per group: min = 123
F(2, 113) = 3.10 avg = 123.00
Prob > F = 0.049 max = 123
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| Robust
ind | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
ind |
L1. | .0422941 .0990663 0.43 0.670 -.153974 .2385622
|
rat | .0013943 .0007611 1.83 0.070 -.0001135 .0029022
_cons | .0090873 .0140751 0.65 0.520 -.018798 .0369727
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Instruments for first differences equation
Standard
D.rat
GMM-type (missing=0, separate instruments for each period unless collapsed)
L(1/123).L.ind collapsed
Instruments for levels equation
Standard
rat
_cons
GMM-type (missing=0, separate instruments for each period unless collapsed)
D.L.ind collapsed
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Arellano-Bond test for AR(1) in first differences: z = -1.21 Pr > z = 0.225
Arellano-Bond test for AR(2) in first differences: z = 0.99 Pr > z = 0.322
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Sargan test of overid. restrictions: chi2(122) =4926.04 Prob > chi2 = 0.000
(Not robust, but not weakened by many instruments.)
Hansen test of overid. restrictions: chi2(122) = 110.60 Prob > chi2 = 0.761
(Robust, but weakened by many instruments.)
Difference-in-Hansen tests of exogeneity of instrument subsets:
GMM instruments for levels
Hansen test excluding group: chi2(121) = 109.34 Prob > chi2 = 0.768
Difference (null H = exogenous): chi2(1) = 1.26 Prob > chi2 = 0.261
iv(rat)
Hansen test excluding group: chi2(121) = 110.31 Prob > chi2 = 0.747
Difference (null H = exogenous): chi2(1) = 0.29 Prob > chi2 = 0.588
Sargan和Hansen不一致。。。。如何取舍?
无论如何,我始终无法使Sargan和AR(2)同时满足。。。
不行不行的了。。。