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Re: [XP] Re: cons of XP -- fixed bid contracts

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  • drawstho@aol.com
    ... But you re missing two of the points of XP - 1. the Customer drives, and 2. you never promise functionality, only effort. The Development team *never*
    Message 1 of 38 , Mar 1, 2002
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      Peter Hansen <peter@...> writes:

      > Laurent Bossavit wrote:
      > >
      > > > Phrase "money then spent so far" implies something other than
      > > > fixed-price contract, doesn't it?
      > >
      > > It does, it does.
      > >
      > > > I agree with the moral principle, but not that it comes to play much
      > > > in fixed-price until the final result is delivered to the customer.
      > >
      > > Doesn't that observation nail the problem down exactly ?
      >
      > Maybe. I'm sorry, but I got lost. Must come from waking in the middle
      > of the night and starting to reply to mailing list messages. :-(
      > Maybe we cut too much context.
      >
      > > > With other methods, the remaining 10% is the 10% that takes another 90%
      > > > of the time, while with XP delivering business value in priority order,
      > > > that 10% might realistically represent 10% (or even less, or slightly
      > > > more) of the remaining time.
      > >
      > > I'm missing something. "10% of the remaining time" I understand -
      > > that was the point of my remark. You say that some other 10%
      > > "represents" less or more of that 10% of the time; my question is,
      > > that other 10% is 10% of ***what*** ?
      >
      > Ah, that's 10% of the promised functionality. Yes, clearly that
      > is very hard to measure, but my point was that if XP focuses on
      > delivering the riskiest and highest business value first, then
      > when you've got 90% through the esimated time, you're very likely
      > to have close to 10% (or even less) of the remaining work to do
      > in terms of functionality/risk/business value, and therefore about
      > 10% (or even less) of the remaining time. At least that's my theory.
      > Or maybe it was more of a question for the group. :)

      But you're missing two of the points of XP - 1. the Customer drives, and 2. you never promise functionality, only effort. The Development team *never* knows how much work there is left to do - the Customer decides when it is done. If the Customer did not select the most valuable stuff to do first, then the Customer was not doing his/her job. By definition, this is outside the scope of the XP development team. If it's inside the scope of your contractual arrangement with your Client you have a problem, but it's not a problem that XP will help you solve... it's probably one of those "cons to XP" we were discussing earlier - "Must have a Customer that is empowered to drive"

      Dan ;-)
      >
      > -Peter
      >
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    • Jim Standley
      Ooops, you sure did. I gotta read more slowly, and write more slowly yet. ... From: Peter Hansen To:
      Message 38 of 38 , Mar 2, 2002
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        Ooops, you sure did. I gotta read more slowly, and write more slowly yet.

        ----- Original Message -----
        From: "Peter Hansen" <peter@...>
        To: <extremeprogramming@yahoogroups.com>
        Sent: Friday, March 01, 2002 11:58 PM
        Subject: Re: [XP] Re: cons of XP -- fixed bid contracts


        > Jim Standley wrote:
        > >
        > > Peter Hansen wrote:
        > > > I also don't really agree that one can't reasonably accurately
        > > > label a project 90% complete at some point in time near the end,
        > > > if one is using XP. With other methods, the remaining 10% is the
        > > > 10% that takes another 90% of the time, while with XP delivering
        > > > business value in priority order, that 10% might realistically
        > > > represent 10% (or even less, or slightly more) of the remaining time.
        > > >
        > > Really? You have a list of stories with estimates. By the time you're
        > > nearly done you should be able to do very good estimates for the rest.
        When
        > > the estimate for the rest = 1/9 of what you've already done ...
        >
        > Uh, I really think we're saying exactly the same thing. The only
        > difference is I unwisely used a confusing double-negative in my first
        > sentence... Sorry about that! :)
        >
        > > This discussion misses that at 90% done XP should have demonstrated some
        > > other values:
        >
        > I hope we didn't miss these things at all. I thought we'd covered all
        > of them by this point.
        >
        > > * When you're 90% done, you have 90% of the stories 100% done, not 100%
        of
        > > them 90% done.
        > > * The customers have value for their money. If they stop the project,
        they
        > > get what they paid for.
        > > * The customers have a good sense of project velocity. They can decide
        with
        > > confidence whether or not to go over budget and keep going.
        > > * The developers have proven themselves over and over by delivering
        useful
        > > stuff. Or not.
        > > * BTW: Any project that is +- 10% is pretty darned close!
        >
        > Yup. Agrees with what I believe.
        >
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