Panel data Conversion to Stationary!

[Linh Tran]

Hi everyone,

I have annual panel data that covers 30 regions, in 7 years.

First of all, I tested Panel unit root in Eviews and found that some variables are not stationary and just have become stationary after 1st or 2nd differences.

Now I want to use these data (in excel file) to run with Panel threshold model in R-software. I don't really understand how to adjust/convert them to become stationary (in excel). Could you please tell me what need I do with my panel data before estimating in R (because they are still non-stationary)?

Thanks in advance!