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


From   Michel Serafinelli <serafine@econ.berkeley.edu>
To   statalist@hsphsun2.harvard.edu
Subject   Re: Re: st: exit variable in opreg by Yasar, Raciborski, Poi (2008)
Date   Fri, 2 Mar 2012 15:32:19 -0800

Dear Nick,

Thanks for your message.

However, I am still puzzled, because tax_code and firmid_op are stored
as double (see output below under -describe-) and still
the exit variable is wrong.

I would really appreciate any suggestions.

I understand that this is a issue not strictly related to -opreg- but
I decided to mention the paper

Yasar, Raciborski, Poi (2008)
“Production function estimation in Stata using the Olley and Pakes method”
The Stata Journal (2008) 8, Number 2, pp. 221–231

because they show how to construct the exit variable, and I was
puzzled by the fact
that using their commands I could not create the right exit variable.

Plus, I think the procedure by

Olley, G. S., and A. Pakes. 1996. The dynamics of productivity in the
telecommunications
equipment industry. Econometrica 64: 1263–1297

implemented by -opreg- is one of the best known examples in which the
exit of a firm is important.

That is why I mentioned opreg. I am sorry if this created confusion.

I copy below the new output from the log file.

Best,

Michel


. xtset tax_code year
       panel variable:  tax_code (unbalanced)
        time variable:  year, 1995 to 2001, but with gaps
                delta:  1 unit

.
. gen double firmid_op=tax_code

. des

Contains data from dataset_for_opreg.dta
  obs:        17,032
 vars:             4                          1 Mar 2012 20:31
 size:       579,088 (99.9% of memory free)   (_dta has notes)
------------------------------------------------------------------------------------------------------------------------------------
              storage  display     value
variable name   type   format      label      variable label
------------------------------------------------------------------------------------------------------------------------------------
year            float  %10.0g
matr_az         str10  %10s
tax_code        double %10.0g
firmid_op       double %10.0g
------------------------------------------------------------------------------------------------------------------------------------
Sorted by:  tax_code  year
     Note:  dataset has changed since last saved

. duplicates list tax_code year

Duplicates in terms of tax_code year

(0 observations are duplicates)

. duplicates list firmid_op year

Duplicates in terms of firmid_op year

(0 observations are duplicates)

.
. sort firmid_op year

. by firmid_op: gen count = _N

. * my dataset is for the period 95-2001 while YRP have data for 95-2002
. gen survivor = count == 7

. gen has95 = 1 if year == 2001
(14464 missing values generated)

. sort firmid_op has95

. by firmid_op: replace has95 = 1 if has95[_n-1] == 1
(10848 real changes made)

. replace has95 = 0 if has95 == .
(3616 real changes made)

. sort firmid_op year

. by firmid_op: gen has_gaps = 1 if year[_n-1] != year-1 & _n != 1
(16414 missing values generated)

. sort firmid_op has_gaps

. by firmid_op: replace has_gaps = 1 if has_gaps[_n-1] == 1
(1921 real changes made)

. replace has_gaps = 0 if has_gaps == .
(14493 real changes made)

. by firmid_op: generate exit = survivor == 0 & has95 == 0 & has_gaps
!= 1 & _n == _N

. replace exit = 0 if exit == 1 & year == 2001
(0 real changes made)

. * now we can see that this is not working
. xtset firmid_op year
       panel variable:  firmid_op (unbalanced)
        time variable:  year, 1995 to 2001, but with gaps
                delta:  1 unit

. *note: matr_az is the string variable corresponding to the
identifier "tax_code/firmid_op" (1:1 relantionship between the two)
. br

. list in 1/30

     +----------------------------------------------------------------------------------------+
     | year      matr_az    tax_code   firmid_op   count   survivor
has95   has_gaps   exit |
     |----------------------------------------------------------------------------------------|
  1. | 1995   1000009303   1.000e+09   1.000e+09       7          1
   1          0      0 |
  2. | 1996   1000009303   1.000e+09   1.000e+09       7          1
   1          0      0 |
  3. | 1997   1000009303   1.000e+09   1.000e+09       7          1
   1          0      0 |
  4. | 1998   1000009303   1.000e+09   1.000e+09       7          1
   1          0      0 |
  5. | 1999   1000009303   1.000e+09   1.000e+09       7          1
   1          0      0 |
     |----------------------------------------------------------------------------------------|
  6. | 2000   1000009303   1.000e+09   1.000e+09       7          1
   1          0      0 |
  7. | 2001   1000009303   1.000e+09   1.000e+09       7          1
   1          0      0 |
  8. | 1996   1000022830   1.000e+09   1.000e+09       6          0
   1          0      0 |
  9. | 1997   1000022830   1.000e+09   1.000e+09       6          0
   1          0      0 |
 10. | 1998   1000022830   1.000e+09   1.000e+09       6          0
   1          0      0 |
     |----------------------------------------------------------------------------------------|
 11. | 1999   1000022830   1.000e+09   1.000e+09       6          0
   1          0      0 |
 12. | 2000   1000022830   1.000e+09   1.000e+09       6          0
   1          0      0 |
 13. | 2001   1000022830   1.000e+09   1.000e+09       6          0
   1          0      0 |
 14. | 1995   1000028092   1.000e+09   1.000e+09       6          0
   0          0      0 |
 15. | 1996   1000028092   1.000e+09   1.000e+09       6          0
   0          0      0 |
     |----------------------------------------------------------------------------------------|
 16. | 1997   1000028092   1.000e+09   1.000e+09       6          0
   0          0      0 |
 17. | 1998   1000028092   1.000e+09   1.000e+09       6          0
   0          0      1 |
 18. | 1999   1000028092   1.000e+09   1.000e+09       6          0
   0          0      0 |
 19. | 2000   1000028092   1.000e+09   1.000e+09       6          0
   0          0      0 |
 20. | 1995   1000035962   1.000e+09   1.000e+09       7          1
   1          0      0 |
     |----------------------------------------------------------------------------------------|
 21. | 1996   1000035962   1.000e+09   1.000e+09       7          1
   1          0      0 |
 22. | 1997   1000035962   1.000e+09   1.000e+09       7          1
   1          0      0 |
 23. | 1998   1000035962   1.000e+09   1.000e+09       7          1
   1          0      0 |
 24. | 1999   1000035962   1.000e+09   1.000e+09       7          1
   1          0      0 |
 25. | 2000   1000035962   1.000e+09   1.000e+09       7          1
   1          0      0 |
     |----------------------------------------------------------------------------------------|
 26. | 2001   1000035962   1.000e+09   1.000e+09       7          1
   1          0      0 |
 27. | 1996   1000039407   1.000e+09   1.000e+09       3          0
   0          0      0 |
 28. | 1997   1000039407   1.000e+09   1.000e+09       3          0
   0          0      1 |
 29. | 1998   1000039407   1.000e+09   1.000e+09       3          0
   0          0      0 |
 30. | 1996   1000053348   1.000e+09   1.000e+09       5          0
   1          1      0 |
     +----------------------------------------------------------------------------------------+





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