I am employing the synthetic control method to establish the effect on labor supply of an intervention on a community. My comparison unit is a synthesize control unit and is created using the synth command. For robustness I am running this analysis on a couple different dimensions of employment (unemployment claims rate, employment level) so I am performing the analysis on a few different data sets. My problem is in establishing my data as a panel. I understand what the problem is, but I do not know how to fix it.

When I attempt xtset I get the error message:

. xtset county date
repeated time values within panel
r(451);

and it makes sense that I get this error message, but how do I rectify this in my dataset? Each county and date has several observations.

This is a general question and am hoping to get an answer that will help me understand the intuition behind xtset. Attached is a capture of my dataset. My data spans January 2018-September 2020 and has observations for every industry and every county in the state of Alaska. Thank you for any help, I am sure my professor is tired of my emails.

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