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# st: RE: Dividing data into quintiles

 From "Radwin, David" <[email protected]> To <[email protected]> Subject st: RE: Dividing data into quintiles Date Mon, 28 Oct 2013 14:58:16 -0400

```Clarice,

If I understand correctly, you merely need to loop through each value of yrmonth and calculate quintiles for observations with that value for yrmonth. But you can't generate a new variable 151 times.

So you could do something this that creates quintiles for a temporary variable:

gen quintile = .
quietly levelsof yrmonth, local(levs)
foreach lev of local levs {
tempvar quint
xtile `quint' = return if rtype=="formation" & yrmonth == "`lev'", n(5)
replace quintile = `quint'
}

David
--
Senior Research Associate
Education and Workforce Development Division
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Phone: 510-665-8274

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> -----Original Message-----
> From: [email protected] [mailto:owner-
> [email protected]] On Behalf Of Clarice Martins
> Sent: Monday, October 28, 2013 11:39 AM
> To: [email protected]
> Subject: st: Dividing data into quintiles
>
> Dear group,
>
> I need to select a sub-group of my dataset and cut it into quintiles, in
> order to proceed with calculations with top and bottom quintile.
>
> - I use Stata 12.1 (for Mac)
>
> - my data looks like this (now, after considerations from the group, thank
> you!)
>
> co_id ticker rtype	yrmonth return
> 1 ABCB formation jun2000 0.01
> 1 ABCB buysell jul2000 0.01
> 1 ABCB holding ago2000 0.01
> 2 AEDU formation jun2000 0.01
> 2 AEDU buysell jul2000 0.01
> 2 AEDU holding ago2000 0.01
> 3 AMBV formation jun2000 0.01
> 3 AMBV buysell jul2000 0.01
> 3 AMBV holding ago2000 0.01
>
> - i tryed both -egen cut- and -xtile-
>
> egen quintile = cut(return) if rtype=="formation", group(5)
>
> xtile quintile=return if rtype=="formation", n(5)
>
> - when I use -if rtype=="formation"- both commands work fine!
>
> - But, I need to select all observations rtype=="formation"  AND
> yrmonth=="jun2000", then cut this subgroup into quintiles
>
> - Then, I need to proceed with this filter/select and cut, for every
> yrmonth (151 periods) on my data set
>
> Any suggestions?
>
> Thank you very much!
>
> Clarice

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```