## Wednesday, November 7, 2012

### Granger Causality Testing in R

Today just gets better and better!

I had an email this morning from Christoph Pfeiffer, who follows this blog. Christoph has put together some nice R code that implements the Toda-Yamamoto method for testing for Granger causality in the context of non-stationary time-series data.

Given the ongoing interest in the various posts I have had (here, here, here & here) on testing for Granger causality, I'm sure that Christoph's code will be of great interest to a lot of readers.

Thanks for sharing this with us, Christoph.

1. For what it's worth, it easier and more flexible to carry out the analysis in R using the VAR package and its causality tests. The EViews analysis can be matched exactly by using exogen option for the lag 7 variables. The only tricky bit is making sure that a proper matching sample is used. When the bootstrapping or voc.=vcovHC options are used, Granger causality is rejected for both variables at any reasonable significance level.

1. Thanks Terry - that's very helpful.

DG

2. Dear Mr. Giles,

The number of parameters to be tested in the Wald-test has the same number as the lags. So if we create an even and an odd sequence in the R-code it will be quite automatic.

Like:
waldtest1<-wald.test(b=coef(V$varresult[[1]]), Sigma=vcov(V$varresult[[1]]), Terms=c(seq(2, by=2, length=lag)))
waldtest2<-wald.test(b=coef(V$varresult[[2]]), Sigma=vcov(V$varresult[[2]]), Terms=c(seq(1, by=2, length=lag)))

I guess it needs a supervision but worked well for me.

Best Regards,
János

3. Thanks János!