I am running a fixed effects regression and am getting the following error:
fixed_effects <- plm(GNI ~ lag(GNI) + imposition + ExpImp + democ, data = sanctions_data6, index = c("country", "sanctions_period"), model = "within", effect = "twoways") duplicate couples (time-id) Error in pdim.default(index[], index[]) :
I am aware that it means that i have duplicate time periods for the same observations. However the whole observations are not duplicates of each other as they represent different types of sanctions imposed.
country sanctions_period sanction_type (chr) (chr) (int) 1 Afghanistan 1995-2002 4 2 Afghanistan 1995-2002 7 3 Afghanistan 1995-2002 NA
How can i get around this problem and run a regression in order to see the results? Thanks!