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st: About taking log on zero values
From
Sebastian Say <[email protected]>
To
[email protected]
Subject
st: About taking log on zero values
Date
Wed, 19 Feb 2014 13:44:15 -0600
Hi my question is about how stata treats a log-transformed variable
that draws upon an original variable that contains zero.
In my dataset, i have firm sales data but some of them have zero. I
created a logsales variable and noticed that those with zeros are
indicated as a "."
I plan to run a regression, e.g.
reg y x1 x2 logsales
My question is, how would stata treat these "." if I do not remove them?
Technically the "." should be undefined.
I've read some papers and they usually put a 1 for those sales data
with zeros in them. Is this a usual practice?
Thank you very much.
Seb
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