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RE: st: RE: rank error?


From   "Nick Cox" <[email protected]>
To   <[email protected]>
Subject   RE: st: RE: rank error?
Date   Wed, 28 May 2003 12:46:09 +0100

Jeph Herrin
 
> Nick Cox wrote:
> > 
> > I think Melony is correct.
> > 
> > The documentation is terse, but I don't think either it 
> or the code is
> > in error.
> > 
> 
> I'll allow that the documentation is ambiguous: "the track
> option calculates the track rank of -exp-; the lowest value
> is ranked 1, and there is no correction for ties. Two values that
> are tied for 2nd remain rank 2". One reading of this is that
> two values tied for lowest would both be ranked 1; values tied
> for the next lowest value would be ranked 2. I see now that
> one doesn't have to read it that way.

Note to Stata Corp: fix the documentation please. 

> > I think what Jeph may be looking for is the -unique- option.
> > 
> 
> Not at all; -unique- assigns different ranks to values of -var1-
> having the same value. I want all values of -var1- to have the
> same rank, and I want to the ranks to be consecutive integers.
> 
> If one wants to do a certain operation on all obs with -var1-==X,
> indexing through all the values of X, and do so in order of 
> increasing
> X, then the value of such a ranking becomes obvious.
> 

Now we have convergence. Try -egen, group()-. 

BTW: have a look also at -levels-. 

Nick 
[email protected] 
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