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Re: st: Again-Unique Case ID in Large Panel


From   Suzy <[email protected]>
To   [email protected]
Subject   Re: st: Again-Unique Case ID in Large Panel
Date   Wed, 04 Aug 2004 13:47:28 -0400

above the duplication option is a unique identifier option - that might help you.

Stephen V. Burks wrote:


Hi, Suzy.

OK, if you are correct then both version of -duplicates- agree that I have no
duplicates. But, this means they both still disagree with -xtdes-, right?

My original starting point was that -xtdes- says I do not have unique identifcation,
but other approaches (now including both versions of -duplicates-) say that this
is incorrect, and I should (do) have unique identification.

Is there another misinterpretation on my part buried somewhere here?

Thanks,
Steve

P.S. just got Nick's post which seems to agree with me, once I accept Suzy's
interpretation on -duplicates-.

At 12:24 PM 8/4/2004, you wrote:


I believe that your output is saying that you have one copy of 1322511 with no surpluses (no duplicates). I just ran this yesterday with my much smaller dataset and was able to verify this.
Suzy

Stephen V. Burks wrote:


Hi, Folks.

Now I wonder if I am reporting a bug.  As per Nick's suggestion
(thanks, Nick) I looked up -duplicates- and ran it.

Results:
(1) using -duplicates report-

. duplicates report  DRVNUM  CDATE

Duplicates in terms of DRVNUM CDATE
--------------------------------------
   copies | observations       surplus
----------+---------------------------
        1 |      1322511             0
--------------------------------------

(2) using -duplicates list-

. duplicates list  DRVNUM  CDATE
Duplicates in terms of DRVNUM CDATE
(0 observations are duplicates)


If I read this correctly, one version of -duplicates- says I have
a single duplicate (the last case in the file), while the other
says I have none. Also, -xtdes- still says that DRVNUM and
CDATE do not uniquely identify cases.

I looked in the data browser, and the last case is NOT a duplicate.
While DRVNUM is the same as the case before, CDATE is not.

If my interpretation of the output is correct then my best guess is
that -xtdes- is wrong to say I do not have unique identification,
and whatever bug causes this might also be behind the apparently
incorrect response from -duplicates report-.  In any event, it seems
to be a problem that -duplicates list- and -xtdes- do not agree.

Any better ideas?

Thanks,
Steve

P.S. My version of Stata is 8.2 for WinXP, with current updates.

--------------------------------------------------
*Stephen V. Burks, Ph.D.
*Assistant Professor of Economics and Management
*University of Minnesota, Morris
*
*Division of Social Sciences
*600 East 4th Street
*Morris, MN 56267-2134
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*
* "Striving to be the Best National
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*
*   For searches and help try:
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--------------------------------------------------
*Stephen V. Burks, Ph.D.
*Assistant Professor of Economics and Management
*University of Minnesota, Morris
*
*Division of Social Sciences
*600 East 4th Street
*Morris, MN 56267-2134
*
*Voice: (320) 589-6191
*Division Staff: (320) 589-6200
*FAX: (320) 589-6117
*E-Mail: [email protected]
*
* "Striving to be the Best National
* Public Liberal Arts College in the U.S."
--------------------------------------------------- *
* 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/


*
*   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/



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