Hi, I have the following question about the panel data analysis in the STATA: Some of the data series I use for my macro panel analysis are stationary I (0) and some are nonstationary I (1). My question is whether or not there is any panel analysis method similar to the ARDL bound model in the time series in the sense that I (0) and I (1)series are evaluated together or should I take the first difference of the I(1) series and put them into regression? Thank you very much, Özgür,