VECMCAUSE.RPF is an example of testing for causality in a VECM. This has separate tests for causality and long-run causality.


The data are 3 and 6 month US TBill yields. Because these don't trend, the appropriate choice for the Johansen test (done with @JOHMLE) is DET=RC (constant restricted to the cointegrating vector):


@johmle(lags=nlags,det=rc,cv=cv)

# tb3mo tb6mo


Based upon the output, we conclude that the series are cointegrated. The further analysis is done with the estimated cointegrating vector:


set z = cv(1)*tb3mo+cv(2)*tb6mo+cv(3)


The CV(3) is there because of the use of DET=RC. The constant is included there and not in the error correction representation. Error correction regressions are estimated for each of the series, regressing the difference on lagged "Z" and the lags of both differenced series. This does the regression for the 3 month rate:


set d3mo = tb3mo-tb3mo{1}

set d6mo = tb6mo-tb6mo{1}


linreg d3mo

# z{1} d3mo{1 to nlags-1} d6mo{1 to nlags-1}


(Note: there is no CONSTANT because the cointegrating model is DET=RC). The overall causality test for the 6 month to 3 month is testing jointly for zeros on Z{1} and the lags of D6MO:


exclude(title="Test for 6MO causing 3MO")

# z{1} d6mo{1 to nlags-1}


and the test for long-run causality looks at Z{1} only:


exclude(title="Test for 6MO long-run causing 3MO")

# z{1}


The results show long-run causality from 6MO to 3MO


The reverse direction tests are done with the analogous:


linreg d6mo

# z{1} d3mo{1 to nlags-1} d6mo{1 to nlags-1}

exclude(title="Test for 3MO causing 6MO")

# z{1} d3mo{1 to nlags-1}

exclude(title="Test for 3MO long-run causing 6MO")

# z{1}


The results here show causality but not long-run causality from 3MO to 6MO.

Full Program


open data w-tb3n6ms.txt
calendar(w) 1958:12:12
data(format=free,top=2,org=columns) 1958:12:12 2004:8:6 tb3mo tb6mo
*
* Test for cointegration. (We should test for unit roots first, but it's
* fairly well-known that these are non-stationary).
*
compute nlags=10
*
@johmle(lags=nlags,det=rc,cv=cv)
# tb3mo tb6mo
*
* We conclude that the two series are cointegrated. The rest of this
* uses the estimated cointegrating vector, though a theoretical value
* (in this case (1,-1)) could also be used.
*
set z = cv(1)*tb3mo+cv(2)*tb6mo+cv(3)
*
set d3mo = tb3mo-tb3mo{1}
set d6mo = tb6mo-tb6mo{1}
*
* 6 causing 3
*
linreg d3mo
# z{1} d3mo{1 to nlags-1} d6mo{1 to nlags-1}
exclude(title="Test for 6MO causing 3MO")
# z{1} d6mo{1 to nlags-1}
exclude(title="Test for 6MO long-run causing 3MO")
# z{1}
*
* 3 causing 6
*
linreg d6mo
# z{1} d3mo{1 to nlags-1} d6mo{1 to nlags-1}
exclude(title="Test for 3MO causing 6MO")
# z{1} d3mo{1 to nlags-1}
exclude(title="Test for 3MO long-run causing 6MO")
# z{1}

Output

Likelihood Based Analysis of Cointegration

Variables:  TB3MO TB6MO

Estimated from 1959:02:20 to 2004:08:06

Data Points 2373 Lags 10 with Constant restricted to Cointegrating Vector


Unrestricted eigenvalues and -T log(1-lambda)

  Rank    EigVal   Lambda-max  Trace  Trace-95%   LogL

       0                                        3225.2802

       1    0.0259    62.3562 67.0737   20.1600 3256.4583

       2    0.0020     4.7175  4.7175    9.1400 3258.8170


Cointegrating Vector for Largest Eigenvalue

TB3MO    TB6MO     Constant

5.319718 -5.375225   1.128813



Linear Regression - Estimation by Least Squares

Dependent Variable D3MO

Weekly Data From 1959:02:20 To 2004:08:06

Usable Observations                      2373

Degrees of Freedom                       2354

Centered R^2                        0.1334503

R-Bar^2                             0.1268242

Uncentered R^2                      0.1334558

Mean of Dependent Variable       -0.000535188

Std Error of Dependent Variable   0.212736745

Standard Error of Estimate        0.198789464

Sum of Squared Residuals         93.023608385

Log Likelihood                       475.9999

Durbin-Watson Statistic                1.9979


    Variable                        Coeff      Std Error      T-Stat      Signif

************************************************************************************

1.  Z{1}                         -0.017101378  0.004080792     -4.19070  0.00002884

2.  D3MO{1}                       0.052434528  0.050425930      1.03983  0.29852445

3.  D3MO{2}                      -0.181149552  0.050481690     -3.58842  0.00033948

4.  D3MO{3}                      -0.068750983  0.051100938     -1.34540  0.17862706

5.  D3MO{4}                       0.097109180  0.050711964      1.91492  0.05562422

6.  D3MO{5}                      -0.067968381  0.050557673     -1.34437  0.17895727

7.  D3MO{6}                      -0.112841890  0.050401548     -2.23886  0.02525828

8.  D3MO{7}                       0.098750478  0.050231057      1.96592  0.04942467

9.  D3MO{8}                      -0.067073655  0.048796087     -1.37457  0.16939552

10. D3MO{9}                       0.106837695  0.048705265      2.19356  0.02836486

11. D6MO{1}                       0.261721396  0.055864536      4.68493  0.00000296

12. D6MO{2}                       0.209471878  0.056306025      3.72024  0.00020369

13. D6MO{3}                       0.096165935  0.056789132      1.69339  0.09051428

14. D6MO{4}                      -0.060031557  0.056530885     -1.06192  0.28837869

15. D6MO{5}                       0.097089164  0.056315322      1.72403  0.08483417

16. D6MO{6}                       0.165910068  0.055984745      2.96349  0.00307226

17. D6MO{7}                      -0.225042143  0.055952339     -4.02203  0.00005952

18. D6MO{8}                       0.104141828  0.054811972      1.89998  0.05755741

19. D6MO{9}                      -0.157050531  0.054790232     -2.86640  0.00418862


Test for 6MO causing 3MO


Null Hypothesis : The Following Coefficients Are Zero

Z                Lag(s) 1

D6MO             Lag(s) 1 to 9

F(10,2354)=     12.75506 with Significance Level 0.00000000


Test for 6MO long-run causing 3MO


Null Hypothesis : The Following Coefficients Are Zero

Z                Lag(s) 1

t(2354)=  -4.190700 or F(1,2354)=  17.561969 with Significance Level 0.00002884



Linear Regression - Estimation by Least Squares

Dependent Variable D6MO

Weekly Data From 1959:02:20 To 2004:08:06

Usable Observations                      2373

Degrees of Freedom                       2354

Centered R^2                        0.1141866

R-Bar^2                             0.1074132

Uncentered R^2                      0.1141963

Mean of Dependent Variable       -0.000627897

Std Error of Dependent Variable   0.189616152

Standard Error of Estimate        0.179143300

Sum of Squared Residuals         75.545325958

Log Likelihood                       722.9349

Durbin-Watson Statistic                1.9983


    Variable                        Coeff      Std Error      T-Stat      Signif

************************************************************************************

1.  Z{1}                         -0.003605806  0.003677492     -0.98051  0.32693671

2.  D3MO{1}                      -0.028232969  0.045442386     -0.62129  0.53446798

3.  D3MO{2}                      -0.009897222  0.045492635     -0.21756  0.82779347

4.  D3MO{3}                      -0.043994419  0.046050684     -0.95535  0.33949994

5.  D3MO{4}                       0.127715368  0.045700151      2.79464  0.00523789

6.  D3MO{5}                      -0.095529392  0.045561109     -2.09673  0.03612386

7.  D3MO{6}                      -0.058179627  0.045420414     -1.28091  0.20035019

8.  D3MO{7}                       0.052914689  0.045266772      1.16895  0.24254128

9.  D3MO{8}                      -0.072366890  0.043973619     -1.64569  0.09996135

10. D3MO{9}                       0.064662009  0.043891773      1.47321  0.14082682

11. D6MO{1}                       0.307452051  0.050343500      6.10709  0.00000000

12. D6MO{2}                       0.054514688  0.050741357      1.07436  0.28276968

13. D6MO{3}                       0.076150520  0.051176719      1.48799  0.13688709

14. D6MO{4}                      -0.079513381  0.050943994     -1.56080  0.11870539

15. D6MO{5}                       0.079280714  0.050749736      1.56219  0.11837773

16. D6MO{6}                       0.092612714  0.050451829      1.83567  0.06653312

17. D6MO{7}                      -0.157359766  0.050422625     -3.12082  0.00182538

18. D6MO{8}                       0.108200135  0.049394960      2.19051  0.02858506

19. D6MO{9}                      -0.110082952  0.049375368     -2.22951  0.02587389


Test for 3MO causing 6MO


Null Hypothesis : The Following Coefficients Are Zero

Z                Lag(s) 1

D3MO             Lag(s) 1 to 9

F(10,2354)=      2.54456 with Significance Level 0.00471672


Test for 3MO long-run causing 6MO


Null Hypothesis : The Following Coefficients Are Zero

Z                Lag(s) 1

t(2354)=  -0.980507 or F(1,2354)=   0.961394 with Significance Level 0.32693671