pescadf GDP , lags(2) trend , this is stata command for Pesaran (2007)

Thanks So much, Kazi Sohag. I am so grateful. Am trying to build by variables based on a paper i am understudying. the variables used by the paper are GDPpc = Debt pc + Capital pc

Pc = Per capita . this made the assumption that using per capita variables imposes a constant returns to scale on the production fuction. I wish to add other variables to the ones above ,

but my question is, if trade (EX+IM) , Population growth and inflation are added to the above specification, will ii amount to violating the constant returns to scale assumption of the production function?

I appreciate help, please.

You can use Eviews where yo find diverse panel contrast to unit roots and cointegration