[Dev] Estimates and bug fix rates

[Lisa Dusseault]

I think a more accurate way to look at this is that we were really only 
focused on fixing bugs from Feb 7 to Mar 28.  Since bugzilla doesn't 
track a past history of "bugs open at this point in time", I tracked 
that over the bug-fixing time period manually (summary at 
http://wiki.osafoundation.org/bin/view/Chandler/ZeroPointFiveRelease).

If we assume that most of the bugs fixed in 0.5 were fixed in that 
7-week period, then we fix 48 bugs/week (2.5 bugs per week per 
developer, perhaps, but I don't think we have 20 developers actively 
fixing most bugs).  I know that doesn't separate out the tasks and bugs 
that were fixed during the feature part of the cycle but we could sure 
try to do that.  By that accounting, we need to allocate 5 weeks 
towards fixing already-known bugs (assuming that we actually want to 
fix them, not postpone bugs which might actually be feature requests) 
and an unknown amount of time fixing currently-unfound bugs.

In 0.4 we went from 120 open bugs to 0 in a period of three weeks, but 
that's not an accurate count of fix/week because it's an absolute count 
(doesn't count incoming bugs) and because of a triage event that 
eliminated 40-50 of those bugs.

Since build and doc bugs are so different from code bugs, I left those 
out of my tracking entirely, so that could indicate another discrepancy 
in these estimates.

Lisa

On Apr 5, 2005, at 6:01 PM, Heikki Toivonen wrote:

> Since we've been using Bugzilla a lot more than before I think it is
> finally starting to give some roughly usable statistics about fix rates
> etc. we can use in planning, for example give us estimates of how long
> will it take to fix a certain number of bugs or estimate when we could
> achieve a release if we were to fix a certain number of bugs.
>
> We still do a lot of checkins that don't have bugs assigned to them, 
> and
> do some other things which result in somewhat inaccurate numbers, so
> these should be understood to just give us some ideas where we stand.
> They should act as a reality check for us, though.
>
> In 0.5 release cycle we fixed roughly 340 bugs, which were assigned to
> 23 people, or about 17 developers. 0.5 cycle lasted 5 months, so this
> gives us a fix rate of about 4 bugs per developer per month.
>
> We have 273 bugs targeted for 0.6 release. Assuming we'd have to fix
> them all, have 20 developers working on them and each fixing 4 bugs per
> month we'd be looking at 0.6 happening roughly three and a half months
> from now.
>
> --
>   Heikki Toivonen
>
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