Stata uses different storage types (see - help datatypes-) to store
numbers, and these types accommodate different levels of precision. By
default Stata will store numbers as "float" which only have 7 digits of
accuracy. You should store identifiers as either "long" or "double" types
(in your case, with 10 or more digits, as "double"). Better would be to
store identifiers as strings, unless there is a good reason to do
otherwise. This avoids the numeric precision problem altogether.
Apart from -help datatypes- there are some useful FAQs on the matter,
-findit precision- leads to some. The Users Manual, section 16.10 has a
discussion.
Phil
At 05:20 PM 4/02/2004 -0800, you wrote:
of more than 10 digits, and find that in some cases, the STATA does not
distinguish two different individuals when the first 9 digits of the id
are the same for the two individuals. For example, suppose that there are
two individuals whose ids are 1234567890 and 1234567891, respectively, -
the ids differ only in the last digit. Then, the STATA displays the two
ids in a scientific notation like 1.234E+9 and seems to treat the two
individuals as the same one. I am wondering if there is a way to have the
STATA distinguish them. I found a similar problem when a variable has more
than 9 digits following the decimal point.
Hyung-Jai Choi
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Philip Ryan
Associate Professor,
Department of Public Health
Associate Dean (Information Technology)
Faculty of Health Sciences
University of Adelaide 5005
South Australia
tel 61 8 8303 3570
fax 61 8 8223 4075
http://www.public-health.adelaide.edu.au/
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