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merging and sample size [was: Re: st: Re: ESTIMATING THE LA/AIDS MODEL]
From
Maarten Buis <[email protected]>
To
[email protected]
Subject
merging and sample size [was: Re: st: Re: ESTIMATING THE LA/AIDS MODEL]
Date
Wed, 13 Jun 2012 14:40:00 +0200
On Wed, Jun 13, 2012 at 2:27 PM, daniel milandu wrote:
> after merging data sets is my sample size supposed to increase
That can happen when the "using dataset" (the dataset you specified
after -using-) contains observations form which no match was found in
the master dataset (the dataset that was open when you called
-merge-). After merging you can see where each observation comes from
(i.e. both datasets, only the master, or only the using dataset) by
looking at the variable _merge. You can than decide whether this
represents a problem or that you can safely drop (some) unmatched
observations.
Hope this helps,
Maarten
--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany
http://www.maartenbuis.nl
--------------------------
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