Re: ANNOUNCE: Ada success story in IEEE Software

["Pat Rogers" <progers@classwide.com>]

"Wes Groleau" <wesgroleau@spamcop.net> wrote in message
news:3C3DAF46.F75BBD@spamcop.net...
>
>
> Pat Rogers wrote:
> > In a study described in a paper published in 1986, Herbert and Myron Hecht
found
> > that for each million lines of code, 20,000 bugs existed.  Normally 90%
would be
> > found by testing.  Another 200 would be found during the first year of
operation
> > by users, leaving 18,000 undetected bugs.  Regular maintenance would fix 200
> > bugs, but also introduce 200 new ones.
>
> This confuses me.  Typos?
>
> Are the 90% found in testing not fixed?  How are 18,000 of them
> still undetected a year after release.

Yes, mea culpa -- a typo (in my original notes, which it cut-and-pasted). That
should be 1800, not 18,000.

> And how can any study detect 18,000 bugs that neither the testers
> nor the users can detect?

The users eventually detected them.