表二十三:协整关系的拟合结果
Dependent Variable: Y Method: Least Squares Date: 06/18/09 Time: 01:29 Sample: 1985 2007 Included observations: 23
Variable
H R
R-squared Adjusted R-squared S.E. of regression Sum squared resid Log likelihood
Coefficient 3.716304 1.279709
Std. Error 0.188912 0.169737
t-Statistic 19.67217 7.539363
Prob. 0.0000 0.0000 2.435461 0.329807 1.830928 1.929667 0.683721
-1.950818 Mean dependent var -2.091333 S.D. dependent var 0.579874 Akaike info criterion 7.061324 Schwarz criterion -19.05568 Durbin-Watson stat
然后,对上述拟合模型的残差序列的平稳性进行检验,运用单位根检验方法。
表二十四:残差序列的单位根检验
Null Hypothesis: E1 has a unit root Exogenous: Constant Lag Length: 1 (Fixed)
t-Statistic -3.154122 -3.788030 -3.012363 -2.646119
Std. Error 0.180210 0.206706 0.094453
t-Statistic -3.154122 1.989080 1.447224
Prob.* 0.0377
Prob. 0.0055 0.0621 0.1650 0.037371 0.485868 1.172967 1.322185 5.230991 0.016183
Augmented Dickey-Fuller test statistic Test critical values:
1% level 5% level 10% level
*MacKinnon (1996) one-sided p-values.
Dependent Variable: D(E1) Method: Least Squares Date: 06/18/09 Time: 01:32 Sample (adjusted): 1987 2007
Augmented Dickey-Fuller Test Equation
Included observations: 21 after adjustments
Variable E1(-1) D(E1(-1))
C
R-squared Adjusted R-squared S.E. of regression Sum squared resid Log likelihood Durbin-Watson stat
Coefficient -0.568406 0.411155 0.136694
0.367577 Mean dependent var 0.297308 S.D. dependent var 0.407287 Akaike info criterion 2.985891 Schwarz criterion -9.316154 F-statistic 1.971621 Prob(F-statistic)
该残差序列是存在截距项的平稳序列,因此,y,h,r之间存在协整关系。虽然变量均为非平稳,但长期来看,三者之间依然存在稳定的关系,不是伪回归。根据文章最初的做法,带截距项的拟合结果如下:
表二十五:协整检验后的拟合结果
Dependent Variable: Y Method: Least Squares Date: 06/18/09 Time: 01:45 Sample: 1985 2007 Included observations: 23
Variable
C H R
R-squared Adjusted R-squared S.E. of regression Sum squared resid Log likelihood Durbin-Watson stat
Coefficient 1.756720 1.108311 0.196094
Std. Error 0.066584 0.104009 0.050317
t-Statistic 26.38351 10.65596 3.897184
Prob. 0.0000 0.0000 0.0009 2.435461 0.329807 -1.660188 -1.512080 111.3375 0.000000
0.917585 Mean dependent var 0.909344 S.D. dependent var 0.099302 Akaike info criterion 0.197219 Schwarz criterion 22.09216 F-statistic 0.732837 Prob(F-statistic)
十八、误差修正模型
协整后的拟合结果基本反映了长期均衡的一种关系,但从短期来看,变量之间的关系一般都会偏离长期均衡,产生波动性。为反映短期的状态,以及短期变动与长期均衡之间的关系,可以通过误差修正模型进行分析。考虑建立以下形式的模型。
llit?ili?yt????hi?0???i?0?rt?i????yii?0t?i?1??et?1?vt
Y的变动分解为因变量的变动、y滞后变量以及上期偏离长期均衡的残差三种因素。对l取不同的值,依次拟合,去掉不显著的滞后项。
通过对l取3,2,1,0,依次拟合,获得的误差修正模型为如下结果(l取2):
表二十六:误差修正模型拟合变量的获取(l=2)
Dependent Variable: D(Y) Method: Least Squares Date: 06/18/09 Time: 02:55 Sample (adjusted): 1989 2007
Included observations: 19 after adjustments
Variable D(H) D(H(-1)) D(H(-2)) D(R) D(R(-1)) D(R(-2)) D(Y(-1)) D(Y(-2)) D(Y(-3)) E11(-1)
R-squared Adjusted R-squared S.E. of regression Sum squared resid Log likelihood
Coefficient 1.055683 -0.664608 -0.286715 0.174388 -0.058563 -0.110846 0.840402 0.367857 0.336834 -1.092134
Std. Error 0.128375 0.262956 0.269575 0.066733 0.060006 0.063462 0.275479 0.279620 0.145549 0.325796
t-Statistic 8.223409 -2.527450 -1.063583 2.613210 -0.975962 -1.746656 3.050694 1.315560 2.314230 -3.352207
Prob. 0.0000 0.0324 0.3152 0.0281 0.3546 0.1146 0.0138 0.2208 0.0459 0.0085 -0.039132 0.147140 -2.406533 -1.909459 2.424848
0.910205 Mean dependent var 0.820410 S.D. dependent var 0.062355 Akaike info criterion 0.034993 Schwarz criterion 32.86206 Durbin-Watson stat
根据以上的结果,去除不需要的变量,取D(H), D(H(-1)), D(R), D(Y(-1)), D(Y(-3)), E11(-1)作为误差修正模型的解释变量进行拟合,拟和结果如下:
表二十七:误差修正模型
Dependent Variable: D(Y) Method: Least Squares Date: 06/19/09 Time: 07:58 Sample (adjusted): 1989 2007
Included observations: 19 after adjustments
Variable D(H) D(H(-1)) D(R) D(Y(-1)) D(Y(-3)) E11(-1)
R-squared Adjusted R-squared S.E. of regression Sum squared resid Log likelihood
Coefficient 0.957754 -0.418689 0.116783 0.574534 0.271678 -0.579737
Std. Error 0.108816 0.223213 0.047688 0.240402 0.133037 0.199748
t-Statistic 8.801609 -1.875739 2.448871 2.389892 2.042114 -2.902336
Prob. 0.0000 0.0833 0.0293 0.0327 0.0620 0.0124 -0.039132 0.147140 -2.449487 -2.151244 2.201195
0.868944 Mean dependent var 0.818538 S.D. dependent var 0.062679 Akaike info criterion 0.051073 Schwarz criterion 29.27013 Durbin-Watson stat
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十九、实证分析
最初的模型拟合结果为:
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这一模型粗略反映了政府公共投资、私人部门固定资产投资以及社会人力资本投资的产出贡献情况,初步分析可知,政府公共投资的效率很低,对国内生产总值的贡献为负;私人部门固定资产的产出贡献率和社会人力资本投资贡献率为正,但后者大大高于前者。由于模型检验结果存在一定的问题,通过规模报酬不变的线形约束,修正的模型拟合结果如下:
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该模型的直观含义是,单位公共投资产出额、人力资本投资额与公共投资配比情况、私人部门固定资产投资额与公共投资配比情况之间的关系。这一模型能