I am not clear what the issue is here. The complaint
seems to be that Stata does what you tell it to do,
and not something else that you want.
I'd recommend a look at
How do I identify runs of consecutive observations in panel data?
http://www.stata.com/support/faqs/data/panel.html
by Vince Wiggins and friend, which may help.
Nick
[email protected]
Carter Ivan Rees
> There are duplicate commands already written for Stata, run help
> duplicates.
>
> The following link has also come in handy for me in the past
> if you are
> looking to count the recurrence of a particular individual
> across time.
>
> Your issue of consecutive years would require the code offered here to
> be tweaked a bit.
>
> http://www.stata.co.uk/support/faqs/data/dups.html
Roberto
> I am currently trying to run a GMM estimation using the xtabond2
> command.
>
> I have an unbalanced panel so I would want to manipulate my
> dataset in a
> way that Stata only keeps the continuous observations for
> each firm For
> example consider these 3 firms
>
> code name year run maxrun _spell _seq _end
> n
> N
> 135540 A 1995 1 5 1 1 1
> 1
> 6
> 135540 A 1997 1 5 2 1 0 2
> 6
> 135540 A 1998 2 5 2 2 0 3
> 6
> 135540 A 1999 3 5 2 3 0 4
> 6
> 135540 A 2000 4 5 2 4 0 5
> 6
> 135540 A 2001 5 5 2 5 1 6
> 6
> 900327 B 1991 1 7 1 1 0 1
> 10
> 900327 B 1992 2 7 1 2 0 2
> 10
> 900327 B 1993 3 7 1 3 1 3
> 10
> 900327 B 1995 1 7 2 1 0 4
> 10
> 900327 B 1996 2 7 2 2 0 5
> 10
> 900327 B 1997 3 7 2 3 0 6
> 10
> 900327 B 1998 4 7 2 4 0 7
> 10
> 900327 B 1999 5 7 2 5 0 8
> 10
> 900327 B 2000 6 7 2 6 0 9
> 10
> 900327 B 2001 7 7 2 7 1 10
> 10
> 134982
> C 1997 1 1 1 1 1 1 3
> 134982 C 1999 1 1 2 1 1 2
> 3
> 134982 C 2001 1 1 3 1 1 3
> 3
>
>
> with the tsspell command I have been able to identify the
> maximum number
> of consecutive observations per firms.
> The problem is that if I write
> keep if maxrun>=5
> stata only drops firm "C" whereas I would want it to drop all the
> non-consecutive observations in all panels so that the database would
> look
> like:
>
> code name year
> 135540 A 1997
> 135540 A 1998
> 135540 A 1999
> 135540 A 2000
> 135540 A 2001
> 900327 B 1995
> 900327 B 1996
> 900327 B 1997
> 900327 B 1998
> 900327 B 1999
> 900327 B 2000
> 900327 B 2001
>
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