st: Re: Using NEARMRG

["Michael Blasnik" <michael.blasnik@verizon.net>]

I'm the author of nearmrg.  The help message is quite clear here and, 
although you may have tried "many things" it doesn't seem like those things 
included addressing the error message.  The nearvar must be unique in the 
using dataset within levels of the varlist (region in your case).  In your 
case, the combination of region and age do not uniquely identify the using 
dataset observations and so the nearest match can not be determined since 
there may be more than one.  -nearmrg- serves as a lookup function and you 
have a lookup table with non-unique (and therefore ambiguous) values.

The sort order of your data does not matter since nearmrg appends the 
datasets together and does its own sorting.

Michael Blasnik
michael.blasnik@verizon.net


----- Original Message ----- 
From: "MA V" <ma_v@hotmail.com>
To: <statalist@hsphsun2.harvard.edu>
Sent: Wednesday, April 26, 2006 5:59 PM
Subject: st: Using NEARMRG



> I just came across a very interesting function named "nearmrg" and I have a 
> question regarding its use:
> If I write:
>
> neamrg region using ageinfo2, nearvar(age) keep
>
> In this case, I have the following questions:
> 1) "age" must be unique in the using dataset, right?
> 2) does the variable region need to be unique?
> 3) how should I sort the variables?
>
> I tried many different things and I always seem to get the message:
>
> "region age not unique in using dataset
> something that should be true of your data is not"
>
> Any suggestions?
> Thanks for your help!!
*
*   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/