st: Synth - Quarterly Data

["Fonseca-Ferreira,V (pgt)" <V.Fonseca-Ferreira@lse.ac.uk>]

Dear all, 

I am studying counter factual GDP responses of the 2004 European Union entrants during the crisis in the absence of the Euro, and I intend to use the Synthetic Control Group Method from Alberto Abadie (synth command in stata). 
I have been trying to run it with quarterly data,but Stata does not seem to be able to recognize it, even though it seems to understand that I am working with quarterly data, according to the tsset function:

. tsset  Country date
       panel variable:  Country (strongly balanced)
        time variable:  date, 1993q2 to 2013q4
                delta:  1 quarter

When I try to run : 
synth  ln_GDP ln_GDP_1 ln_C ln_I ln_GC ln_X ln_M , trunit(33) trperiod(2007q1)figure counit(6 16 21 22 28) xperiod(1995q2(1) 2006q4) mspeperiod(1995q2(1) 2006q4) resultsperiod(1995q2(1) 2013q3) nested keep(Slovenia)

I get the error message "trperiod() invalid -- invalid number r(121);" where trperiod(2007q1) is the period the treatment "Euro" was introduced in Slovenia. I believe the problem lies in the "q" in "2007q1", and that this would also be a problem for xperiod; mspeperiod; and resultsperiod. Any ideas on how can I correct this? ​


Thanks,​
Best Regards,

Vitor Ferreira

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