st: exit variable in opreg by Yasar, Raciborski, Poi (2008)

[rraciborski@stata.com]

Michel Serafinelli <serafine@econ.berkeley.edu> is having trouble constructing
an exit variable based on the code provided in Yasar, Raciborski, and Poi
(2008, p.227).

> [On] pag[e] 227 of their article, YRP show the commands on how to construct
> the exit variable. However this does not seem to work for me.

We noticed that the code on page 227 is missing a line.

    (code omitted)
  . replace has_gaps = 0 if has_gaps==.
  . by firmid : generate exit = survivor==0 & has95==0 & has_gaps!=1 & _n==_N 
  . replace exit = 0 if exit==1 & year==2002

should read

  . replace has_gaps = 0 if has_gaps==.
  . sort firmid year
  . by firmid : generate exit = survivor==0 & has95==0 & has_gaps!=1 & _n==_N 
  . replace exit = 0 if exit==1 & year==2002

--Rafal
rraciborski@stata.com

References

M. Yasar, R. Raciborski, and B. Poi. 2008. Production function estimation in
Stata using the Olley and Pakes method, 8(2), 221-231.
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