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Re: [XP] Re:fixed-price fixed-scope projects

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  • Bob.Jarvis@chase.com
    ... Keith - Do you have a source for that statistic? (It could be helpful.) BJ
    Message 1 of 13 , Apr 1, 2005
      Keith Ray wrote:

      > A commonly-repeated statistic is that on a typical project, 6% of
      > requirements change every month. (new, modified, deleted).

      Keith - Do you have a source for that statistic? (It could be helpful.)

      BJ
    • Jeff Grigg
      ... I thought it was 1% a month. (6% a month would be pretty scary. 6% times 12 months, is 72%!!!) _ _ _ A quote: Creeping Requirements Endemic to the
      Message 2 of 13 , Apr 1, 2005
        > --- Keith Ray wrote:
        >> A commonly-repeated statistic is that on a typical project, 6% of
        >> requirements change every month. (new, modified, deleted).

        --- Bob.Jarvis@c... wrote:
        > Keith - Do you have a source for that statistic?
        > (It could be helpful.)

        I thought it was 1% a month.

        (6% a month would be pretty scary. 6% times 12 months, is 72%!!!)
        _ _ _

        A quote:

        Creeping Requirements
        Endemic to the Software Industry
        - Occurs on more than 70% of all applications over 1000 function
        points
        From a 60 project sample
        - Average creep was 35%
        - Maximum observed was 200%
        - Creeping requirements change about 1% per month
        - - For a 3 year project, 1/3 of the delivered requirements would
        have been added after requirements were initially defined

        Rate of Requirements change is higher than for other forms of
        engineering (electrical, mechanical, civil)

        Source: Assessment and Control of Software Risks,
        Capers Jones, 1994
      • acockburn@aol.com
        Yep, probably was a statistical fluke. Everyone did understand that the details would change over time, that s partly the reason the client (!) insisted on
        Message 3 of 13 , Apr 1, 2005
          Yep, probably was a statistical fluke. Everyone did understand that the
          details would change over time, that's partly the reason the client (!) insisted
          on deliveries every quarter. And we did have in plan, and did, pick up the use
          cases for each quarter's cycle and recheck and fine tune them in that
          quarter - and there were some changes, of course, because the world turns. And we
          had two user viewings within each cycle, so they changed the requirements
          again, but usually not too violently. And, of course, there was some sort of
          contractual mechanism in place around this too ...

          ...but all in all, not much changed. As several people picked up, this was
          the 3rd try, so they probably knew their business pretty well by then.

          ... and, as I said, I have come to realize just how spoilt I was, working on
          this as my first fixed-price, fixed-scope project. The agile approach helped
          us, of course, but the general management savvy and good natured exchanges
          between client and supplier were enormous factors.

          ... It could be a statistical fluke that all those factors came together on
          one project ...
          (but if we could peel those apart and try to increase odds on other
          projects, what factors
          would we work to replicate?...)

          Alistair

          In a message dated 3/31/2005 11:23:39 A.M. Mountain Standard Time,
          extremeprogramming@yahoogroups.com writes:


          --- In extremeprogramming@yahoogroups.com, yahoogroups@j... wrote:
          > I think he already said. This was Alistair's message that kicked
          > off this subthread; Alistair is the one that said the requirements
          > stayed stable for 18 months.
          >
          > Part of it is that it was the third attempt, so the problems with
          > understanding the domain and what the customer wanted were
          > quite likely already shaken out.
          >
          > However, the external world doesn't stand still for a year and
          > a half. Competitors change, the market changes, executives
          > come and go. Even with perfect domain knowledge and a
          > customer who does know what he wants, 18 months without
          > substantial change is a statistical fluke.





          ==============================================
          Alistair Cockburn
          President, Humans and Technology

          801.582.3162
          1814 Ft Douglas Cir,
          Salt Lake City, UT 84103
          _http://alistair.cockburn.us/_ (http://alistair.cockburn.us/)
          acockburn@...
          (fax: 484.970.8954)
          ===============================

          "Surviving Object-Oriented Projects" (1998)
          "Writing Effective Use Cases" (Jolt Productivity Award 2001)
          "Agile Software Development" (Jolt Productivity Award 2002)
          "Crystal Clear: A Human-Powered Methodology for Small Teams" (Jolt Award
          Finalist 2004)

          "La perfection est atteinte non quand il ne reste rien a ajouter,
          mais quand il ne reste rien a enlever." (Saint-Exupery)

          "The first thing to build is trust." (Brad Appleton)
          ==============================================




          [Non-text portions of this message have been removed]
        • Keith Ray
          That s it. ... -- C. Keith Ray
          Message 4 of 13 , Apr 1, 2005
            That's it.

            On Apr 1, 2005, at 9:35 AM, Jeff Grigg wrote:

            >
            >
            >> --- Keith Ray wrote:
            >>> A commonly-repeated statistic is that on a typical project, 6% of
            >>> requirements change every month. (new, modified, deleted).
            >
            > --- Bob.Jarvis@c... wrote:
            >> Keith - Do you have a source for that statistic?
            >> (It could be helpful.)
            >
            > I thought it was 1% a month.
            >
            > (6% a month would be pretty scary. 6% times 12 months, is 72%!!!)
            > _ _ _
            >
            > A quote:
            >
            > Creeping Requirements
            > Endemic to the Software Industry
            > - Occurs on more than 70% of all applications over 1000 function
            > points
            > From a 60 project sample
            > - Average creep was 35%
            > - Maximum observed was 200%
            > - Creeping requirements change about 1% per month
            > - - For a 3 year project, 1/3 of the delivered requirements would
            > have been added after requirements were initially defined
            >
            > Rate of Requirements change is higher than for other forms of
            > engineering (electrical, mechanical, civil)
            >
            > Source: Assessment and Control of Software Risks,
            > Capers Jones, 1994
            >
            >
            >
            >
            >
            > To Post a message, send it to: extremeprogramming@...
            >
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            >
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            --
            C. Keith Ray
            <http://homepage.mac.com/keithray/blog/index.html>
            <http://homepage.mac.com/keithray/xpminifaq.html>
            <http://homepage.mac.com/keithray/resume2.html>
          • Adrian Howard
            On 1 Apr 2005, at 18:35, Jeff Grigg wrote: [snip] ... I don t know. I ve seen worse :-) I did some work for a .com startup where we had monthly meetings with
            Message 5 of 13 , Apr 5, 2005
              On 1 Apr 2005, at 18:35, Jeff Grigg wrote:
              [snip]
              > I thought it was 1% a month.
              >
              > (6% a month would be pretty scary. 6% times 12 months, is 72%!!!)

              I don't know. I've seen worse :-)

              I did some work for a .com startup where we had monthly meetings with
              the CEOs. There entire business plan seemed to change every time we say
              them which, to there seemingly unceasing surprise, caused us to throw
              away most of what we'd done the previous month.

              Needless to say they're not around anymore.

              I wish I'd known more about agile methods then - it would have made
              life easier.

              Cheers,

              Adrian
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