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Re: st: a question about an identifying variable with more than 10 digits

From   Philip Ryan <[email protected]>
To   [email protected]
Subject   Re: st: a question about an identifying variable with more than 10 digits
Date   Thu, 05 Feb 2004 12:03:05 +1030

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.


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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