st: RE: Puzzling error with merge

[Joe Canner <jcanner1@jhmi.edu>]

David,

I find that my eyes play tricks on me when I try to look at a frequency distribution to determine if the identifier is unique.  Just to be on the safe side, see what happens when you do the following on the master data set:

duplicates report StudyID

Regards,
Joe Canner
Johns Hopkins University School of Medicine

________________________________________
From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] on behalf of David Hoaglin [dchoaglin@gmail.com]
Sent: Monday, January 13, 2014 7:42 AM
To: statalist@hsphsun2.harvard.edu
Subject: st: Puzzling error with merge

Dear All,

I attempted to merge two datasets, each of which has 247 observations,
with the following command:

merge 1:1 StudyID using Sheet2

(here "Sheet2" is the last part of the fully qualified name of the
file, recently imported from Excel).

I received the following error message: "variable StudyID does not
uniquely identify observations in the master data".

I then tabulated StudyID in the two files.  Each output showed no
frequency other than 1 and a total of 247 observations.

What am I doing wrong?

I am using Stata 13.1.

Thanks for your help.

David Hoaglin
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