Bugs to Code Ratio
Nice insight.
https://www.mayerdan.com/ruby/2012/11/11/bugs-per-line-of-code-ratio
(a) Industry Average: "about 15 - 50 errors per 1000 lines of delivered
code." He further says this is usually representative of code that has some
level of structured programming behind it, but probably includes a mix of
coding techniques.
(b) Microsoft Applications: "about 10 - 20 defects per 1000 lines of code
during in-house testing, and 0.5 defect per KLOC (KLOC IS CALLED AS 1000 lines of code) in released
product (Moore 1992)." He attributes this to a combination of code-reading
techniques and independent testing (discussed further in another chapter of
his book).
(c) "Harlan Mills pioneered 'cleanroom development', a technique that has
been able to achieve rates as low as 3 defects per 1000 lines of code during
in-house testing and 0.1 defect per 1000 lines of code in released product
(Cobb and Mills 1990). A few projects - for example, the space-shuttle
software - have achieved a level of 0 defects in 500,000 lines of code using
a system of format development methods, peer reviews, and statistical
testing."