一、问题综述
建立中国宏观经济模型。宏观经济模型,是指以整个国民经济系统为研究对象,从总量水平和经济结构方面来研究国民经济各变量之间的相互作用。它可用来评价宏观经济、分析宏观经济结构和国民经济的发展趋势。宏观经济模型的表达可以用单一方程进行表达,也可以用联立方程组表达。
本作业建立如下宏观经济模型,完备的结构式模型为
其中,包含3个内生变量,即国内生产总值Y,居民消费总额C和投资总额I;3个先决变量,即消费G,前期居民消费总额Ct-1和常数项。
可以判断,消费方程是恰好识别的方程,投资方程是过度识别的,模型可以识别。数据来自题目提供。导入EVIEWS
二、各种方法的EVIEWS实现
1.狭义的工具变量法估计消费方程
选取消费方程中未包含的先决变量G作为内生解释变量Y的工具变量;
在工作文件主窗口点击quick/estimate equation,选择估计方法TSLS,在equation specification对话框输入消费方程,在instrument list对话框输入工具变量.
点击确定,得到:
| Dependent Variable: C01 | ||||
| Method: Two-Stage Least Squares | ||||
| Date: 06/02/11 Time: 14:08 | ||||
| Sample (adjusted): 1979 2009 | ||||
| Included observations: 31 after adjustments | ||||
| Instrument list: C G C01(-1) | ||||
| Variable | Coefficient | Std. Error | t-Statistic | Prob. |
| C | 1290.053 | 402.7353 | 3.203229 | 0.0034 |
| Y | 0.107133 | 0.023150 | 4.627739 | 0.0001 |
| C01(-1) | 0.785756 | 0.071859 | 10.93471 | 0.0000 |
| R-squared | 0.998513 | Mean dependent var | 34025.26 | |
| Adjusted R-squared | 0.998407 | S.D. dependent var | 34218.49 | |
| S.E. of regression | 1365.679 | Sum squared resid | 52222209 | |
| F-statistic | 9402.761 | Durbin-Watson stat | 0.743434 | |
| Prob(F-statistic) | 0.000000 | Second-Stage SSR | 53379247 | |
2.间接最小二乘法估计消费方程
消费方程中包含的内生变量的简化方程为
参数关系体系为
用普通最小二乘法估计第一个简化式:
| Dependent Variable: C01 | ||||
| Method: Least Squares | ||||
| Date: 06/02/11 Time: 14:46 | ||||
| Sample (adjusted): 1979 2009 | ||||
| Included observations: 31 after adjustments | ||||
| Variable | Coefficient | Std. Error | t-Statistic | Prob. |
| C | 1086.594 | 386.5534 | 2.810981 | 0.00 |
| C01(-1) | 0.954538 | 0.036256 | 26.32772 | 0.0000 |
| G | 0.265581 | 0.058021 | 4.577310 | 0.0001 |
| R-squared | 0.998480 | Mean dependent var | 34025.26 | |
| Adjusted R-squared | 0.998372 | S.D. dependent var | 34218.49 | |
| S.E. of regression | 1380.725 | Akaike info criterion | 17.39037 | |
| Sum squared resid | 53379247 | Schwarz criterion | 17.52914 | |
| Log likelihood | -266.5507 | Hannan-Quinn criter. | 17.43561 | |
| F-statistic | 9198.948 | Durbin-Watson stat | 0.743999 | |
| Prob(F-statistic) | 0.000000 | |||
| Dependent Variable: Y | ||||
| Method: Least Squares | ||||
| Date: 06/02/11 Time: 14:47 | ||||
| Sample (adjusted): 1979 2009 | ||||
| Included observations: 31 after adjustments | ||||
| Variable | Coefficient | Std. Error | t-Statistic | Prob. |
| C | -19.134 | 2081.958 | -0.912186 | 0.3695 |
| C01(-1) | 1.575455 | 0.195273 | 8.067950 | 0.0000 |
| G | 2.4792 | 0.312499 | 7.932794 | 0.0000 |
| R-squared | 0.994318 | Mean dependent var | 84244.67 | |
| Adjusted R-squared | 0.993912 | S.D. dependent var | 95306.59 | |
| S.E. of regression | 7436.521 | Akaike info criterion | 20.75796 | |
| Sum squared resid | 1.55E+09 | Schwarz criterion | 20.673 | |
| Log likelihood | -318.7484 | Hannan-Quinn criter. | 20.80320 | |
| F-statistic | 2449.755 | Durbin-Watson stat | 0.686339 | |
| Prob(F-statistic) | 0.000000 | |||
由参数体系计算得到结构参数间接最小二乘估计值为
3.二阶段最小二乘法
点击objects/new object,选择system
| System: UNTITLED | ||||
| Estimation Method: Two-Stage Least Squares | ||||
| Date: 06/02/11 Time: 15:09 | ||||
| Sample: 1979 2009 | ||||
| Included observations: 31 | ||||
| Total system (balanced) observations 62 | ||||
| Coefficient | Std. Error | t-Statistic | Prob. | |
| C(1) | 1290.053 | 402.7353 | 3.203229 | 0.0022 |
| C(2) | 0.107133 | 0.023150 | 4.627739 | 0.0000 |
| C(3) | 0.785756 | 0.071859 | 10.93471 | 0.0000 |
| C(4) | -2538.266 | 948.1448 | -2.677087 | 0.0097 |
| C(5) | 0.441390 | 0.007534 | 58.58576 | 0.0000 |
| Determinant residual covariance | 1.63E+13 | |||
| Equation: C01=C(1)+C(2)*Y+C(3)*C01(-1) | ||||
| Instruments: G C01(-1) C | ||||
| Observations: 31 | ||||
| R-squared | 0.998513 | Mean dependent var | 34025.26 | |
| Adjusted R-squared | 0.998407 | S.D. dependent var | 34218.49 | |
| S.E. of regression | 1365.679 | Sum squared resid | 52222209 | |
| Durbin-Watson stat | 0.743434 | |||
| Equation: I=C(4)+C(5)*Y | ||||
| Instruments: G C01(-1) C | ||||
| Observations: 31 | ||||
| R-squared | 0.991774 | Mean dependent var | 346.51 | |
| Adjusted R-squared | 0.991491 | S.D. dependent var | 42513.37 | |
| S.E. of regression | 3921.722 | Sum squared resid | 4.46E+08 | |
| Durbin-Watson stat | 0.538847 | |||
投资方程的参数估计量为
4.三阶段最小二乘法
| System: UNTITLED | ||||
| Estimation Method: Three-Stage Least Squares | ||||
| Date: 06/02/11 Time: 15:20 | ||||
| Sample: 1979 2009 | ||||
| Included observations: 31 | ||||
| Total system (balanced) observations 62 | ||||
| Linear estimation after one-step weighting matrix | ||||
| Coefficient | Std. Error | t-Statistic | Prob. | |
| C(1) | 1384.346 | 361.6729 | 3.827620 | 0.0003 |
| C(2) | 0.116538 | 0.018109 | 6.435173 | 0.0000 |
| C(3) | 0.756373 | 0.056038 | 13.49746 | 0.0000 |
| C(4) | -2538.266 | 917.0495 | -2.767861 | 0.0076 |
| C(5) | 0.441390 | 0.007287 | 60.57228 | 0.0000 |
| Determinant residual covariance | 1.55E+13 | |||
| Equation: C01=C(1)+C(2)*Y+C(3)*C01(-1) | ||||
| Instruments: G C01(-1) C | ||||
| Observations: 31 | ||||
| R-squared | 0.998459 | Mean dependent var | 34025.26 | |
| Adjusted R-squared | 0.998349 | S.D. dependent var | 34218.49 | |
| S.E. of regression | 1390.396 | Sum squared resid | 54129611 | |
| Durbin-Watson stat | 0.672688 | |||
| Equation: I=C(4)+C(5)*Y | ||||
| Instruments: G C01(-1) C | ||||
| Observations: 31 | ||||
| R-squared | 0.991774 | Mean dependent var | 346.51 | |
| Adjusted R-squared | 0.991491 | S.D. dependent var | 42513.37 | |
| S.E. of regression | 3921.722 | Sum squared resid | 4.46E+08 | |
| Durbin-Watson stat | 0.538847 | |||
消费方程的参数估计量为
投资方程的参数估计量为
5.GMM(广义矩估计)
| System: UNTITLED | ||||
| Estimation Method: Generalized Method of Moments | ||||
| Date: 06/02/11 Time: 15:27 | ||||
| Sample: 1979 2009 | ||||
| Included observations: 31 | ||||
| Total system (balanced) observations 62 | ||||
| Identity matrix estimation weights - 2SLS coefs with GMM standard errors | ||||
| Kernel: Bartlett, Bandwidth: Fixed (3), No prewhitening | ||||
| Coefficient | Std. Error | t-Statistic | Prob. | |
| C(1) | 1290.053 | 616.4117 | 2.092844 | 0.0408 |
| C(2) | 0.107133 | 0.027722 | 3.8537 | 0.0003 |
| C(3) | 0.785756 | 0.093957 | 8.362901 | 0.0000 |
| C(4) | -2538.266 | 1067.430 | -2.377923 | 0.0208 |
| C(5) | 0.441390 | 0.013425 | 32.87845 | 0.0000 |
| Determinant residual covariance | 1.63E+13 | |||
| J-statistic | 1.21E+13 | |||
| Equation: C01=C(1)+C(2)*Y+C(3)*C01(-1) | ||||
| Instruments: G C01(-1) C | ||||
| Observations: 31 | ||||
| R-squared | 0.998513 | Mean dependent var | 34025.26 | |
| Adjusted R-squared | 0.998407 | S.D. dependent var | 34218.49 | |
| S.E. of regression | 1365.679 | Sum squared resid | 52222209 | |
| Durbin-Watson stat | 0.743434 | |||
| Equation: I=C(4)+C(5)*Y | ||||
| Instruments: G C01(-1) C | ||||
| Observations: 31 | ||||
| R-squared | 0.991774 | Mean dependent var | 346.51 | |
| Adjusted R-squared | 0.991491 | S.D. dependent var | 42513.37 | |
| S.E. of regression | 3921.722 | Sum squared resid | 4.46E+08 | |
| Durbin-Watson stat | 0.538847 | |||
消费方程的参数估计量为
投资方程的参数估计量为
三、几种方法的分析比较
由上述各种结果可以看出,狭义的工具变量法(IV)、间接最小二乘法(ILS)、二阶段最小二乘法(2SLS)与广义矩阵法(GMM),都得到了相同的参数估计量。前三种方法都是适用于恰好识别的结构方程,只是使用不同的工具变量估计得到的。
三阶段最小二乘法(3SLS)是一种系统估计方法,是二阶段最小二乘法(2SLS)的推广和发展,并且都是在各个阶段采用了普通最小二乘法(OLS),非常类似。发现3SLS的估计标准误差小于2SLS的估计标准误差,体现了3SLS估计更为有效。
四、总结
对我国1978-2009年部分宏观经济数据宏观经济模型,运用EVIEWS分别运用狭义的工具变量法、间接最小二乘法、二阶段最小二乘法、三阶段最小二乘法和广义矩阵法对模型进行了估计,取得了较好的结果,并略微对各个方法进行了比较。下载本文