luigi,
for opreg to work, some firms must exit the market. if none does, you
may use the user-written -levpet- command which controls for
simultaneity but not the selection bias. -search levpet- will locate
the command for you.
best,
rafal
On Mon, Dec 15, 2008 at 2:37 PM, Luigi Pascali <[email protected]> wrote:
> I need to estimate a production function using the olley-pakes semiparametric estimation procedure. I am using the routine -opreg- (developed by Yasar, Raciborski, & Poi).
> I don't have firms that exit the panel and this seems to be a problem when running opreg.
> The option "exit" in the command is required. For this reason I have constructed a dummy (that I called E) which is equal to 0 in each period for every firm.
> Then I run the following command:
> opreg lY, state(lK) proxy(lI) free(lL lM) exit(E)
>
> where lY=ln(sales)
> lk=ln(fixed assets)
> lL=ln(employees)
> lM=ln(intermediates)
> lI=ln(investments)
>
> I get the following message:
>
> an error occurred when bootstrap executed opreg
> r(2000);
>
> I tried to run the same command "pretending" that some firms where leaving the market and everything worked fine.
> I would really appreciate if anybody could tell me if I am making any mistake and how I can correct it.
>
> Many thanks,
>
> Luigi
>
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