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RE: st: Problem with seed and bootstrap


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: Problem with seed and bootstrap
Date   Mon, 19 Sep 2005 11:20:43 +0100

I've been puzzled by the behaviour of -sort- 
in the past before I understood this, so 
I have some sympathy with Svend's motivation, 
but I want to cry Whoa! here. I suspect that 
some programs or do files actually depend 
on the jiggling around that is standard 
with -sort-. Change the default and you 
break that (or raise yet another version 
control issue). 

For users who need this, 

. sort ... , stable 

or a wrapper to that effect seems easy enough. 

Nick 
n.j.cox@durham.ac.uk 

Svend Juul

> Two messages about unstable and stable sorts:
> 
> Thank you very much Gary. -Sort- was creating the problem
> and the option -stable- solved it.
> ...
> It is interesting that setting the seed does not solve this 
> sort of problem.
> I've always wondered how and why -sort- produces inconsistent 
> results anyway.
> I would think a stable sort is easiest to do, but apparently not.
> I suspect it is a good idea to just pay the performance 
> penalty and get in
> the habit of using the -stable- option routinely.
> ----
> 
> Imagine that -sort ... , stable- was the default, but that you could
> avoid it with an -unstable- option. Can anybody imagine a situation
> where a user would benefit from the -unstable- option?
> 
> A stable sort might take some more computer time (does it?), but quite
> a few users have spent quite some human time trying to figure out what
> happens. A wish to StataCorp.: Let -stable- be the default, and add a
> -fast- or -unstable- option if there is a point in doing that.

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