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• Re: Velocity Experiment [80 hours solo = ?? hours with PP (Re: Productive 80 hour week - was Re: [XP] Re: Weaknesses of XP)]

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• ... First off this example has been hypothetical, so it assumed that there is something, but in general, if I revise an estimate, its because I have reason to
Message 1 of 21 , Jan 1, 2002
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Dale:

>Perhaps you're basing your decision on information you
>haven't told me about. What's the information?

First off this example has been hypothetical, so it assumed that there is
something, but in general, if I revise an estimate, its because I have
reason to in the situation based on my experience with the stories and the
system being built.

>I'm not yet seeing what information you will use to determine which
>estimates were off, or even whether the estimates were off at all.

In my example, the people doing the estimates felt that the 1 point story
was the one that was more difficult than expected.

Try looking at it this way:
Me: "See those bags of flour over there? How much do you think they weigh
relative to each other?"
You: "Hmmm, let's see, the second one looks twice as heavy as the first,
and the third looks three times as heavy."
Me: "OK, could you now estimate these other 50 bags."
(Imaginary Dale does so)
Me: "OK, now go pick some of them up, if you would please."
You: "Sure"
(Imaginary Dale goes over and hefts bags of flour."
Me: "Now what do you think about their relative weights?"
You: "I think there is something weird about that 1 point bag over there,
it seemed almost as heavy as those two point bags."
Me: "Maybe you just imagined it. Here are some more bags, give 'em a heft."
(imaginary Dale kindly obliges)
Me: "Well? What did you find out?"
You: "There is definitely something weird about those little 1 point bags,
I think they are wider than the others or something, because they
definitely are shorter, but they weigh about as much as those 2 point
bags."
Me: "Would you like to revise your estimates?"

Now Dale, perhaps you can answer these questions for me:
a) what information would imaginary you be using to determine the bags'
relative weights?
b) Why is imaginary you doing the re-estimating rather than imaginary me?
c) Why did imaginary you think his estimates were off?
d) How did he "know" that it was the 1 point bag and not the 2 point bag
that was "wrong"?
e) What does imaginary you's revised estimates do for Ron when he comes
along to heft flour?
f) What if they were rated "really heavy", "twice of a pain", and "triple
back surgery", how would that affect the estimates' usefulness to Ron?
g) What if we rated them by how long it would take you to carry them 50
meters, would that change anything?

Best,
Bill
• ... Have you no f5g life? Do you know what time it is??? Ron Jeffries www.XProgramming.com It is not because things are difficult that we do not dare, it is
Message 1 of 21 , Jan 1, 2002
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Around Tuesday, January 01, 2002, 6:07:08 AM, wecaputo@... wrote:

> First off

Have you no f5g life? Do you know what time it is???

Ron Jeffries
www.XProgramming.com
It is not because things are difficult that we do not dare,
it is because we do not dare that they are difficult. --Seneca
• ... Yes. One typical revision will be because with that class of story we forgot something that has to be done. (Ohh, we forgot we have to refactor the
Message 1 of 21 , Jan 1, 2002
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Around Tuesday, January 01, 2002, 6:07:08 AM, wecaputo@... wrote:

> First off this example has been hypothetical, so it assumed that there is
> something, but in general, if I revise an estimate, its because I have
> reason to in the situation based on my experience with the stories and the
> system being built.

Yes. One typical revision will be because with that class of story we
forgot something that has to be done. (Ohh, we forgot we have to
refactor the database for these.)

Another occurs when refactoring or tool-making makes something
formerly difficult really easy. My favorite example of that was when
George announced at one planning meeting that he would do all the rest
(25 or something) of things that he could formerly do a few of per
iteration.

The basic idea, of course, is that these stories are different in
proportion to the others, from what we thought (or from what they
actually were). In that case, it makes sense to adjust them rather
than hope that velocity will handle it, because ... velocity won't
handle it very well.

Ron Jeffries
www.XProgramming.com
Sigs are like I Ching or Tarot. They don't mean anything,
but sometimes if you think about them you'll get a useful idea.
• Yeah, I was up late playing Empire Earth, what was your excuse?? Ron Jeffries
Message 1 of 21 , Jan 1, 2002
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Yeah, I was up late playing Empire Earth, what was your excuse??

Ron Jeffries
<ronjeffries@acm. To: extremeprogramming@yahoogroups.com
org> cc:
Subject: Re: Velocity Experiment [80 hours solo = ?? hours with PP (Re: Productive 80
01/01/2002 05:17 hour week - was Re: [XP] Re: Weaknesses of XP)]
AM
extremeprogrammin
g

Around Tuesday, January 01, 2002, 6:07:08 AM, wecaputo@...
wrote:

> First off

Have you no f5g life? Do you know what time it is???

Ron Jeffries
www.XProgramming.com
It is not because things are difficult that we do not dare,
it is because we do not dare that they are difficult. --Seneca

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• ... ...but wait... why *start* at 40 ? You d be missing a third of the measurable curve outright. If this is to be a proper experiment, you should insist on
Message 1 of 21 , Jan 1, 2002
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> Start the experiment at 40 hours, and go up to 50 and then 60, and it
> would be a fairer experiment, although still not a humane one.

...but wait... why *start* at 40 ? You'd be missing a third of the
measurable curve outright. If this is to be a proper experiment, you
should insist on starting measurement at 0 hour weeks, and moving up
to 168.
-[Morendil]-
Your email has been returned due to insufficient voltage.
• Hi Bill, ... Actually, I can t. Perhaps the Dale you imagined can answer them. Dale
Message 1 of 21 , Jan 1, 2002
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Hi Bill,

> Now Dale, perhaps you can answer these questions for me:

Actually, I can't. Perhaps the Dale you imagined can answer them.

Dale
• Hi Bill, ... Okay. That s good enough for me. Dale
Message 1 of 21 , Jan 1, 2002
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Hi Bill,

> >Perhaps you're basing your decision on information you
> >haven't told me about. What's the information?
>
> First off this example has been hypothetical, so it assumed that
> there is something, but in general, if I revise an estimate, its
> because I have reason to in the situation based on my experience
> with the stories and the system being built.

Okay. That's good enough for me.

Dale
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