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RE: st: Tabulating extreme values


From   "Nick Cox" <[email protected]>
To   <[email protected]>
Subject   RE: st: Tabulating extreme values
Date   Tue, 13 May 2003 10:31:59 +0100

R. Allan Reese
 
> > On Mon, May 12, 2003 at 10:04:15PM +0100, SJ Friederich, 
> Economics wrote:
> > > Say I have a variable taking on a large number of 
> values and I am only
> > > interested in finding out how much each of the top five 
> or ten values
> > > represent in terms of frequencies.
> >
> On Mon, 12 May 2003, Michael Hills wrote:
> 
> > . tab X if X > x
> >
> > might work after a few stabs at different values of x.
> 
> Nearly there, but in one step you can use ranks.  As the 
> rank function
> changes the sort order of the data, it may be advisable to save the
> current order:
> 
> gen corder = _n
> egen rankx = rank(x)
> tab x if rankx < 5
> 
> However, I often advise clients that a very powerful 
> analysis tool is to
> sort and inspect the data editor, since you can see what 
> other variables
> are odd values on the same case.

But, setting aside what happens with ties, 
this is just what -extremes- can do, and 
not I think Sylvain's problem. 

Note that for some while now -egen- doesn't 
change the sort order of observations, 
so the saving of order is unnecessary. 
That dates from Stata 7. 

I think I have extended -extremes- 
so that Sylvain can do what he wants. 
We'll confer privately and report back to the 
list. 

Nick 
[email protected] 

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