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[extremeprogramming] Re: Project Velocity and Load Factors

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  • Robert C. Martin
    ... Hours are probably too fine a granule for this kind of work. Call it 48 days. ... 48 days. Yeah. ... Right. ... Yeah. ... Yeah. ... YEAH! ... This is the
    Message 1 of 5 , Jan 31, 2000
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      > -----Original Message-----
      > From: Arrizza, John [mailto:john_arrizza@...]

      > To make sure I have understood this correctly:
      >
      > 1) During the planning game we commit to the number of total
      > number of ideal
      > weeks we have available. For example, using a starting velocity of 2.5
      > (recommended by Kent I believe):
      >
      > 8 people * 3 week iteration * 40 hours / 2.5 = 960/2.5
      > = 384 hours
      > available.

      Hours are probably too fine a granule for this kind of work. Call it 48
      days.
      >
      > The customers select n stories whose estimates add up to
      > roughly 384 hours.

      48 days. Yeah.

      >
      > 2) The developers go off and create the tasks and estimates
      > for those tasks.
      > We add up the task estimates.

      Right.

      >
      > If the total task estimate is greater than 384, we go back to
      > the customer
      > and ask them which story can be removed or which story can be
      > replaced with
      > one that takes less estimated time. This is repeated until we
      > have a set of
      > tasks that adds up to roughly 384.

      Yeah.

      >
      > If we find the total task estimate to be *substantially* less
      > than 384, we
      > go back and ask for another story to do. This is repeated
      > until we have a
      > set of tasks that adds up to roughly 384.

      Yeah.

      >
      > 3)we do the work.

      YEAH!

      >
      > 4)If we complete the tasks *ahead* of schedule, say by 2
      > days, we adjust the
      > velocity:
      >
      > 13 actual days/15 days * 2.5 orginal factor = 2.2 new factor

      This is the load factor. The velocity was 48 days in 13 days. This is
      about 3.7 days/day, or 55 days/iteration. If your next iteration is the
      same duration (3 weeks) and you haven't changed the team in any way,
      then can simply sign up for 55 days of work.
      >
      > If we complete the tasks *behind* schedule, say by 3 days, we
      > adjust the
      > velocity:
      >
      > 18 actual days/15 days * 2.5 orignal factor = 3.0 new factor

      Again, its simpler to say: We got 50 days worth of work done last
      iteration, so we'll sign up for only 50 this time. You only need to do
      the ratios is you change the duration of the next iteration, or the
      composition of the team.



      Robert C. Martin | OO Mentoring | Training Courses:
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