Stata is reading in my variables as string instead of numeric. What
should I do?
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Title
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Numeric variables input as string
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Author
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Nicholas J. Cox, Durham University, UK
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Date
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October 2001; minor revision February 2002; minor revision October 2005
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Users often find that Stata is reading in most, or even all, variables as
string variables, when most, or even all, are—or should
be—numeric. If a variable is string, then typically Stata refuses to
do calculations. You may even get the cryptic message no
observations, which here means “no numeric values on which to do
that”. A command such as tabulate will also list numeric
values in alphanumeric order, rather than numeric, so that 1,
11, and 2 appear in that order. Most directly,
describe will show string variables as having some storage type from
str1 to str244 and as having a display format ending in
s, such as %9s.
See
help data types to learn more.
One common reason for this problem is that the data have been imported from
a spreadsheet or something similar. Some users of Excel or similar programs
get in the habit of putting several lines of header material before the body
of their data. Although Stata tries to detect such lines, it is not always
successful, and this may have caused each variable to be treated as string.
For a discussion of this and several other possible problems, see the FAQ
“How do I get information
from Excel into Stata?”. Even if your data have been nowhere near
Excel, that FAQ may still be helpful.
The most general remedy is to use the destring command. For example,
typing
. destring, replace
will do the best it can at putting things right. First, however, see
help destring
to learn about its options for special problems, and, especially, check that
there are no header lines in the body of the data. The easiest way to fix
those may be by using the Data Editor.
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