Stata is verifiably accurate
When you submit new drug applications (NDAs), the U.S. Food and Drug
Administration (FDA) requires you to
verify the validity of your data and analyses.
According to this document, to demonstrate the validity of the software used
for an NDA, you must have
- a written design specification;
- a test plan; and
- test results.
Stata provides all three:
- An extensive set of manuals
detailing the syntax, use, formulas, references, and examples for all
of the commands in Stata;
- An extensive software certification suite
consisting of over 1.4 million lines of code testing the computational
validity of Stata’s commands and Stata’s ability to
maintain integrity; and
- The output from running Stata’s test
suite on all supported platforms (Windows, Mac, Unix, etc.).
The test suite produces over 3 million lines of output as of 14
May 2013. This output is electronically compared to previous runs
of the test suite and against runs on other platforms. Any differences
are examined and resolved by our statisticians and software engineers
before a new release of Stata (or any subsequent free updates) is sent
The actual number of tests is even larger than is indicated above.
Many of the tests do not produce output but instead quietly do the
computations and compare them with the correct results. If results are
outside accepted tolerance levels, the test fails.
Information about Stata’s results running the National
Institute of Standards (NIST) StRD
numerical accuracy tests and the George Marsaglia Diehard
random-number generator tests is also available.
The FDA guidance document further discusses change/version control and
documentation of revalidation. All updates to Stata can be obtained by
users over the Internet with the simple Stata command
update. All changes are
documented in Stata’s help system. Users can type help
whatsnew or select Help > What's New? from the menu to
see, listed by date, all changes that have been made to Stata and
included in the currently installed update (as well as previous
Stata has an excellent worldwide reputation for accuracy and quick
resolution of all questions. Should any questions arise about using Stata
when submitting to any government agency (including the FDA), StataCorp will
assist you in resolving the issues by working directly with the government
agency, if needed.