Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down at the end of May, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: dropping incomplete frequencies without 'missing' in panel data


From   Joerg Luedicke <joerg.luedicke@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: dropping incomplete frequencies without 'missing' in panel data
Date   Wed, 13 Jul 2011 11:30:14 -0400

You could do the following:

bys  hhnr: gen nyears=_N
drop if nyears<7

But consider that more often than not, you do not need a completely
balanced panel and dropping households that are not fully observed
over the entire period of 7 years can potentially induce some sort of
bias.

J.

On Wed, Jul 13, 2011 at 10:39 AM, Abdul <bihiabdul@gmail.com> wrote:
> Dear List,
>
> I have a panel dataset and I wanted to drop those observations where
> the variable 'hhnr' is missing in some time periods. for example when
> hhnr is 6, it is only reported in 2001 and not in subsequent years,
> whereas when hhnr is 9, it is reported in all years from 2001 to 2007.
>
> hhnr    year    volumew    valuew
> 6    2001    770    4585
> 9    2001    9374    91672
> 9    2002    13576    145520
> 9    2003    4720    44709
> 9    2004    3429    30254
> 9    2005    5589.25    43225.37
> 9    2006    4577.1    44175.56
> 9    2007    6079.05    74066.045
> 13    2001    1273    11399
> 13    2002    1705    15619
> 13    2003    1306    11060
> 13    2004    728    5823
> 13    2005    331.2    2930.16
> 13    2006    541.2    2900.175
> 13    2007    635.6    2910.115
> 14    2004    467    5893
> 14    2006    360    4548
> 14    2007    897.15    11333.995
> 14    2007    897.15    11333.995
> 18    2001    4308    37267
> 18    2002    1234    13419
>
> If those observations where hhnr is not there were reported as missing
> I could have used this FAQ:
> http://www.stata.com/support/faqs/data/dropmiss.html
> Unfortunately, they are just left out and I am unable to drop them
> despite many attmpts. I would appreciate if you either help me with a
> way to make them explicitly missing in this dataset or yet better if
> you konw a way to drop them and keep only those 'hhnrs' with complete
> frequency (reported in all years).
>
> Thanks,
> Abdul
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
>

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index