Hi Davide!,
Thank you very much!, your trick works perfect!!
Best regards
Claudio
----- Mensaje original -----
De: Davide Cantoni <[email protected]>
Fecha: Martes, Mayo 20, 2008 6:13 pm
Asunto: Re: st: how to balance a panel?
> Hello Claudio,
>
> this is the trick I use when I want to balance a panel (y is the
> outcome variable):
>
> *** begin code
>
> sort id year
> by id: egen nonmissing1to7 = count(y) if (year==1 | year==2 | year==3
> | year==4 | year==5 | year==6 | year==7)
> keep if nonmissing1to7==7
>
> *** end code
>
> Maybe there are more elegant solution around, but this one always
> works fine for me.
>
> Best
>
> Davide
>
>
>
> 2008/5/20 Claudio Cruz Cazares <[email protected]>:
> > Dear all!,
> >
> > I`m working in my Phd. dissertation but a have not find a
> solution for a crucial problem, hope you could help me.
> >
> > I have an unbalanced panel data of 4050 firms in 16 years but I
> have monotone and intermittent (since I clean the data from
> missing values of my dependent variables) missingness and as far
> as I know, the intermittent missingnes could cause problems when
> estimating fist differences.
> >
> > I wonder if someone could tell me how could I clean the sample.
> The easiest thing would be to balance it, but even I can see,
> after xtdes command, how many firms are in all periods, I can not
> find de way to keep just them. Is there any way to select the
> firms based upon their pattern?
> > Other solution is to eliminate the intermittent observations and
> keep those who died during the panel and those who growth within
> the panel, but how can I do that?
> >
> > I have generated a new variable in order to identify the
> missingness of a firm in a year.
> >
> > quietly by Identi: gen dy=year-year[_n-1]
> >
> > dy would be = 1 if there are non missing observation of the
> firm. Then, I drop the firms with a dy > 1. But I still have
> intermittent missigness!
> >
> > xtdes
> >
> > Freq. Percent Cum. | Pattern
> > ---------------------------+-----------------
> > 577 18.89 18.89 | 111111111111111
> > 158 5.17 24.06 | 11 . . . . . . . . . . . . .
> > 150 4.91 28.97 | 1 . . . . . . 11111111
> > 136 4.45 33.42 | . . . . . . . . . . 11111
> > 131 4.29 37.71 | 111111111111 . . .
> > 126 4.12 41.83 | 1 . . . . . . . . . . . . . .
> > 126 4.12 45.96 | 1111 . . . . 111 . . . .
> > 116 3.80 49.75 | 111 . . . . . . . . . . . .
> > 88 2.88 52.64 | 111111 . . . . . . . 11
> > 1447 47.36 100.00 | (other patterns)
> > ---------------------------+-----------------
> > 3055 100.00 | XXXXXXXXXXXXXXX
> >
> >
> >
> >
> > Thanks in advance
> >
> > Claudio
> >
> >
> > *
> > * For searches and help try:
> > * http://www.stata.com/support/faqs/res/findit.html
> > * http://www.stata.com/support/statalist/faq
> > * http://www.ats.ucla.edu/stat/stata/
> >
> *
> * For searches and help try:
> * http://www.stata.com/support/faqs/res/findit.html
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
*
* For searches and help try:
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* http://www.stata.com/support/statalist/faq
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