Hello,

How do I know what is the right way to conduct unit root tests for panel data because I tried different codes and I get different results. These are the two different codes:

xtunitroot ips lnco2, trend demean
xtunitroot ips lnco2, lags(1)

Moreover, do I conduct this tests for the variable before logging and centering or after (the actual variable I want to use for my regressions)?