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Re: st: panel data-dropping all observations for the identifier when certain variable value is missing
From
Nick Cox <[email protected]>
To
[email protected]
Subject
Re: st: panel data-dropping all observations for the identifier when certain variable value is missing
Date
Wed, 6 Jul 2011 08:44:54 +0100
This is quite wrong.
The -keep- command has two basic syntaxes which can not be combined,
so all code here is illegal. In any case if this syntax worked the
effect would be to leave only -xvar- for -date-s greater than 2008,
whereas the problem is different, to drop panels that are too short.
See my earlier post for another suggestion.
Nick
On Wed, Jul 6, 2011 at 4:32 AM, Muhammad Anees <[email protected]> wrote:
> drop xvar if date<datein2008 will drop all those observations with
> missing datein2008 observations too as I guess. but the inverse
> command of -keep-ing will do the job. You can use
>
> keep xvar if date>datein2008
> keep xvar if date>datein2007
> keep xvar if date>datein2006
> etc.
>
>
> Hope this works
> On Wed, Jul 6, 2011 at 5:07 AM, Sabrina Helmut <[email protected]> wrote:
>> I have firm-year observations for the years 2003-2010. For cases where the last value for the variable <offdate>, which is a variable containing dates, is older than a
>> date in 2008 (so date in 2007, 2006,...) then stata shall drop the firm/identifier at all, so for
>> every year. Then, I want stata to show me for every firm/identifier the last entry for the variable <offdate>, which could then either be a date in 2008, 2009 or 2010. Which commands could help me doing this?
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