AlistairCockburn comments about the impact of environment on LoadFactor:
But that is also taking into account your environment, that people are
PairProgramming and have an unnamed partner while programming, and will themselves be partners in programming. That partnering is not written on the board and is somehow magically folded into the
LoadFactor, no one knows exactly how, which is why
LoadFactor is
JustaNumber. It only works in your context for your specific use of it, which is to tell how long something will take your team when they write an estimate on the board. It doesn't necessarily work backwards and it doesn't necessarily work in different contexts and it doesn't work to map other people's logged programming hours to XP staff logged programming hours. --
AlistairCockburn
Of course it is taking our environment into account. Our programmers convert ideal estimates to ideal work in 2.5 days for every ideal day. Since they report in ideal days, it certainly follows that out of 15 days in an iteration, they spend 9 doing something that is NOT recorded as work on one of their tasks. It's a good bet that it is made up of partnering with other people, work on non-tasks, reading, wasting time, etc.
It remains true that if we have a project estimated (by our programmers) as requiring 1,000 ideal days, it will take them about 2,500 real days to do it. It would be nice to know why it's 2,500 and not 2,000 or 3,000, but it isn't necessary to know to do the math.
Am I missing something?
" it certainly follows that out of 15 days in an iteration, they spend 9 doing something that is NOT recorded as work on one of their tasks" This would only follow if you measured time spent "working on tasks". It is equally reasonable to suppose that they spend only half the time on the tasks that the
LoadFactor would indicate, or twice.
But Kent, we DO measure time spent working on tasks. Denny, nee Bob, asks them for IPT done and IPT to go several times an iteration. They are supposed to answer in the same terms as the original IPT estimate. --R
However, Alistair, you seem to be saying that using
IdealProgrammingTime and
LoadFactor together is C3-specific or
ExtremeProgramming-specific. I don't agree at all. People have been doing this (albeit under different names) for decades. I can remember laughing at a manager when he joked about multiplying estimates by two and then moving up the next higher units. I can also remember my chagrin when my next publicly announced two day task took me four weeks.
I can easily believe that "2.5" is project specific, but the estimation method certainly isn't.
--
KentBeck