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Re: st: [merging US industry level data]


From   Scott Cunningham <scunning@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: [merging US industry level data]
Date   Fri, 29 Sep 2006 09:08:03 -0400

I would not use a merge. Merge requires there be a common variable
between datasets. I use this same data a lot. Since 3-digit and
4-digit NAICS data are not "similar", I would append the 3-digit data to
the 4-digit data and create a dummy variable indicating whether the
observation is associated with 3-digit or 4-digit.
Justin,

Not to butt in, but can you elaborate? I have two datasets currently: one on health outcomes where the panel identifier is a state variable which varies over time, and another dataset (the master dataset) where the panel identifier is a state, race, age, and sex specific cell that varies over time. The health data is from 1980-2000, while the master dataset is from 1970-2000. Originally I was using -joinby- but it was causing the master data to drop the 1970-1979 years. So I was going back to -merge-, and had planned to - reshape- the data down to a level where the merge could occur between using and master datasets. But are you saying here that -append- might be better, where a dummy variable indicating the using from the master data? But won't this just extend the length of the master data? For instance, say the data is:

MASTER

race sex age state year vbl1
Black M 15 AL 1970 14.4
Black F 15 AL 1970 4.4
White M 15 AL 1970 .03
White F 15 AL 1970 3.3

...

Black M 15 AL 2000 1.2
Black F 15 AL 2000 11
White M 15 AL 2000 .91
White F 15 AL 2000 12.1


USING

state year vbl2
AL 1980 11
AL 1981 12
...
AL 2000 14.5


My thought was to reshape vbl1 by sex, age and race, as I was saying, so as to create a single state observation, and then merging on that state using the using data. But are you saying that it's easier to use append? Wouldn't it just add teh data to bottom of the master data?


scott
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