On Tue, Sep 20, 2011 at 9:22 AM, Stuart Bishop <stuart.bis...@canonical.com> wrote: > On Tue, Sep 20, 2011 at 6:52 PM, William Grant > <william.gr...@canonical.com> wrote: >> On 20/09/11 21:49, Jeroen Vermeulen wrote: >>> On 2011-09-20 18:04, Stuart Bishop wrote: >>> >>>> This ties into our 256+ critical bugs too. I'd really like to see our >>>> high bugs downgraded to medium and our critical bugs downgraded to >>>> high. This way we can use critical for the stuff that genuinely has to >>>> be fixed right now possibly late at night and on weekends, unlike the >>>> bulk of our existing critical bugs which we hope to deal with in the >>>> next 6 months. 6 months away doesn't match most peoples definition of >>>> critical... >>> >>> I agree. We can't keep creating more Critical bugs than we can handle, >> >> Or perhaps we can't keep handling fewer Critical bugs than we are creating? > > There was a formula from an agile seminar I can never remember where > you take the average time to fix bugs, rate of incoming bugs and end > up with a timeframe. Any bugs hanging around longer than this > timeframe are WONTFIX by definition, because the incoming rate of more > important bugs multiplied by your velocity means you will never get > around to it. So when a bug gets into that list it means one of a) Its > been badly prioritized and you dropped it on the floor b) It will only > be fixed by accident, such as becoming irrelevant or c) You're > screwed. > > Or something like that. Anyone remember? I think my notes are buried > in a box somewhere (Damn paper notes! How last millennium!)
It might be an application of Little's Law: The average number of customers in a queue is equal to the average rate they join the queue multiplied by the average time each customer spends waiting in the queue and being serviced (L = λW). To apply it to bugs: if we have 10 new critical bugs a week on average and each bug spends 3 weeks waiting and 1 week being fixed on average, then we should expect to average 40 critical bugs open. If you decide that there is a deadline of 4 weeks to fix a critical bug, then if your fix rate goes down or your incoming bug rate goes up, something will have to give. Sidebar: The law is more interesting when you only have L (average number in the system) and λ (rate of additions to the queue) and want to know W (how long from the time they enter the system to exiting the system). For example, if we know we average 10 new bugs a week and we know that we average 250 open bugs, then we know that a bug will, on average, be open for 25 weeks. Of course the averages get less and less useful the greater the variance of W. -- Benji York _______________________________________________ Mailing list: https://launchpad.net/~launchpad-dev Post to : launchpad-dev@lists.launchpad.net Unsubscribe : https://launchpad.net/~launchpad-dev More help : https://help.launchpad.net/ListHelp
