[SystemSafety] Estimating time to next fault report

[Derek M Jones]

Martyn,

> The analysis makes some assumptions:
> "(assuming that the report relates to a coding mistake and
> is not a request for enhancement or something the user did wrong,
> and the number of active users remains the same and the program
> is not changed)"

I think that the number of users has a big impact on
number of fault reports.  Any model either has to
assume that number of users is constant, or include
a user growth variable in the model.

An analysis of fixed fault in the Linux Kernel shows a rate
change at around 200 days.  The data records when the coding
mistake was introduced and when it was fixed.

When a new Linux kernel is released, which happens every 80 days or so,
it is not immediately adopted by users.  It takes time for the
new version to be widely adopted.  Over time the number of
users increases, until it is essentially everybody.
The fault fix rate change at around 200 days suggests that at
around 200 days the new version is in widespread usage.

https://shape-of-code.com/2025/11/30/lifetime-of-coding-mistakes-in-the-linux-kernel/

-- 
Derek M. Jones           Evidence-based software engineering
blog:https://shape-of-code.com