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Re: [scrumdevelopment] Communication Load Guess-work

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  • Ron Jeffries
    ... Are they all going to sit in one room? Which of the 15 will be the 3? Are they going to pair program? Will there be team code ownership? Are any of them
    Message 1 of 9 , Jan 27, 2005
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      On Thursday, January 27, 2005, at 4:58:37 PM, Cote' wrote:

      > So, my question is, what are some good numbers to use to get a feeling
      > for the extra time, due to communications overhead, that adding more
      > team members creates?

      Are they all going to sit in one room? Which of the 15 will be the
      3? Are they going to pair program? Will there be team code
      ownership? Are any of them going through significant life changes
      during the project? Have any of them ever been divorced? Are they
      all of the same gender and oriented to the other gender? Are they
      all equally skilled, and if so, how did you accomplish that?

      In other words, the answer, if we had it, will apply to no real case.
      However my guess at the answer is:

      3 7 10 15
      1 1.1 1.5 2.0

      Ron Jeffries
      www.XProgramming.com
      The greatest mistake we make is living in constant fear that we will make one.
      -- John Maxwell
    • chesterdaigle
      Going all the way back to Brooks the mythical man-month his worst case scenario is mostly summarized in these two paragraphs from Chapter 2:
      Message 2 of 9 , Jan 27, 2005
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        Going all the way back to Brooks' 'the mythical man-month' his worst
        case scenario is mostly summarized in these two paragraphs from
        Chapter 2:
        "Intercommunication is worse. If each part of the task must be
        separately coordinated with each other part, the effort increases as
        n(n-1)/2. Three workers require three times as much pairwise
        intercommunication as two; four require six times as much as two. If,
        moreover, there need to be conferences among three, four, etc.,
        workers to resolve things jointly, matters get worse yet. The added
        effort of communicating may fully counteract the division of the
        original task and bring us to the situation of Fig. 2-4.

        Since software construction is inherently a systems effort - an
        exercise in complex interrelationships - communication effort is
        great, and it quickly dominates the decrease in individual task time
        brought about by partitioning. Adding more men then lengthens, not
        shortens, the schedule."

        --- In scrumdevelopment@yahoogroups.com, Ron Jeffries
        <ronjeffries@X...> wrote:
        > On Thursday, January 27, 2005, at 4:58:37 PM, Cote' wrote:
        >
        > > So, my question is, what are some good numbers to use to get a
        feeling
        > > for the extra time, due to communications overhead, that adding
        more
        > > team members creates?
        >
        > Are they all going to sit in one room? Which of the 15 will be the
        > 3? Are they going to pair program? Will there be team code
        > ownership? Are any of them going through significant life changes
        > during the project? Have any of them ever been divorced? Are they
        > all of the same gender and oriented to the other gender? Are they
        > all equally skilled, and if so, how did you accomplish that?
        >
        > In other words, the answer, if we had it, will apply to no real
        case.
        > However my guess at the answer is:
        >
        > 3 7 10 15
        > 1 1.1 1.5 2.0
        >
        > Ron Jeffries
        > www.XProgramming.com
        > The greatest mistake we make is living in constant fear that we
        will make one.
        > -- John Maxwell
      • Ron Jeffries
        ... Brooks was right if you consider communicating among N people as being the same as communicating among N people taken 2 at a time. That s not the only way
        Message 3 of 9 , Jan 27, 2005
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          On Thursday, January 27, 2005, at 7:41:50 PM, chesterdaigle wrote:

          > Going all the way back to Brooks' 'the mythical man-month' his worst
          > case scenario is mostly summarized in these two paragraphs from
          > Chapter 2:
          > "Intercommunication is worse. If each part of the task must be
          > separately coordinated with each other part, the effort increases as
          > n(n-1)/2. Three workers require three times as much pairwise
          > intercommunication as two; four require six times as much as two. If,
          > moreover, there need to be conferences among three, four, etc.,
          > workers to resolve things jointly, matters get worse yet. The added
          > effort of communicating may fully counteract the division of the
          > original task and bring us to the situation of Fig. 2-4.

          > Since software construction is inherently a systems effort - an
          > exercise in complex interrelationships - communication effort is
          > great, and it quickly dominates the decrease in individual task time
          > brought about by partitioning. Adding more men then lengthens, not
          > shortens, the schedule."

          Brooks was right if you consider communicating among N people as
          being the same as communicating among N people taken 2 at a time.
          That's not the only way to do it.

          Ron Jeffries
          www.XProgramming.com
          Will Turner: This is either madness or brilliance.
          Captain Jack Sparrow: It's remarkable how often those two traits coincide.
        • Mike Dwyer
          Reduction of the telephone game is the single biggest overall contribution Scrums and related techniques bring to the table. Take for example if everyone
          Message 4 of 9 , Jan 27, 2005
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            Reduction of the 'telephone game' is the single biggest overall contribution
            Scrums and related techniques bring to the table. Take for example if
            everyone could pass 95% of a message of 100 words to one other person.
            How many people would it take to garble the message? Since Garble is a
            subjective term let's rephrase this to get 50 words changed. (15 people
            ???)

            Now supposing that it took 2 minutes for one person to pass the message onto
            another person, Note the 2 minutes includes, finding the person, getting
            their attention, repeating the message, confirming they got the message and
            the ending the conversation. That would be around 30 minutes for all 15
            people to get the wrong message.

            Now let's add in another 5 minutes per person for correcting the garbled
            message. 2 minutes to find the person, 1 minute to hear what they said, 2
            minutes to repeat the correct message (we will assume that you have either
            recorded the message, have perfect recall, or are reading from a memo.)
            That is 75 minutes.

            So far we have sent one message out and it has cost us 105 work minutes from
            a work day of 400 minutes or about 1.7% of each person's day.

            Does this reflect your work place? I doubt it as the chances of you being
            able to do all of this in the time projected uses the premise that these 15
            people are always free to talk or listen. It also uses the premise that
            none of these 15 people have talked to anyone else, or among themselves.

            Michael F. Dwyer

            Mike.Dwyer1@...



            -----Original Message-----
            From: Ron Jeffries [mailto:ronjeffries@...]
            Sent: Thursday, January 27, 2005 9:05 PM
            To: scrumdevelopment@yahoogroups.com
            Subject: Re: [scrumdevelopment] Re: Communication Load Guess-work


            On Thursday, January 27, 2005, at 7:41:50 PM, chesterdaigle wrote:

            > Going all the way back to Brooks' 'the mythical man-month' his worst
            > case scenario is mostly summarized in these two paragraphs from
            > Chapter 2:
            > "Intercommunication is worse. If each part of the task must be
            > separately coordinated with each other part, the effort increases as
            > n(n-1)/2. Three workers require three times as much pairwise
            > intercommunication as two; four require six times as much as two. If,
            > moreover, there need to be conferences among three, four, etc.,
            > workers to resolve things jointly, matters get worse yet. The added
            > effort of communicating may fully counteract the division of the
            > original task and bring us to the situation of Fig. 2-4.

            > Since software construction is inherently a systems effort - an
            > exercise in complex interrelationships - communication effort is
            > great, and it quickly dominates the decrease in individual task time
            > brought about by partitioning. Adding more men then lengthens, not
            > shortens, the schedule."

            Brooks was right if you consider communicating among N people as
            being the same as communicating among N people taken 2 at a time.
            That's not the only way to do it.

            Ron Jeffries
            www.XProgramming.com
            Will Turner: This is either madness or brilliance.
            Captain Jack Sparrow: It's remarkable how often those two traits coincide.




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          • Ron Jeffries
            ... My point exactly. Ron Jeffries www.XProgramming.com Anyone can make the simple complicated. Creativity is making the complicated simple. -- Charles Mingus
            Message 5 of 9 , Jan 27, 2005
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              On Thursday, January 27, 2005, at 10:51:27 PM, Mike Dwyer wrote:

              > Reduction of the 'telephone game' is the single biggest overall contribution
              > Scrums and related techniques bring to the table.

              My point exactly.

              Ron Jeffries
              www.XProgramming.com
              Anyone can make the simple complicated.
              Creativity is making the complicated simple. -- Charles Mingus
            • David A Koontz
              ... feeling ... Interesting question - I m not sure the absolute numbers mater so much as they are going to be very case specific - but the curve... Here s my
              Message 6 of 9 , Jan 28, 2005
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                > So, my question is, what are some good numbers to use to get a
                feeling
                > for the extra time, due to communications overhead, that adding more
                > team members creates?

                Interesting question - I'm not sure the absolute numbers mater so
                much as they are going to be very case specific - but the curve...

                Here's my guess at the graph of releative communication overhead (y
                axis) to additional team members (x axis)

                1 2 3 4 5 6 7 8 N
                |----|----|----|----|----|----|----|----|
                | +
                |
                |
                |
                |
                |
                | +
                |
                |
                |
                |
                | +
                |
                |
                | +
                |
                |
                | +
                |
                | +
                | +
                | /
                | /
                | /
                |/
                |----|----|----|----|----|----|----|----|
                1 2 3 4 5 6 7 8 N (team members)

                At some point, say above 8 - 15 the graph would quit approaching the
                vertical - but only because lots of effort would be redirected from
                personal communication to group communication and then to mass
                communication. The loss of "message fidelity" would be very
                significant as communication media changes. (I guess that's why I
                never get much out of a political speach - but would love the chance
                to talk one-on-one with the Pres.)
              • David A Koontz
                bummer - that graph looked real good - even in the preview window - but then HTML got in the way - sorry
                Message 7 of 9 , Jan 28, 2005
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                  bummer - that graph looked real good - even in the 'preview' window -
                  but then HTML got in the way - sorry
                • Jeff Sutherland
                  Industry data on exponential loss in productivity with increasing team size can be found in slides 14 and 15 of my Scrum Theory presentation at:
                  Message 8 of 9 , Jan 29, 2005
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                    Industry data on exponential loss in productivity with increasing team
                    size can be found in slides 14 and 15 of my Scrum Theory presentation
                    at:
                    http://jeffsutherland.com/papers/OTUG2003/Scrum_Theory_files/frame.htm

                    Jeff Sutherland


                    On Thu, 27 Jan 2005 15:58:37 -0600, Cote' <bushwald@...> wrote:
                    >
                    > Recently, I playing around with some *extremely* rough guess work
                    > about how long it would take teams of various sizes to complete a set
                    > of work. For example, say I had an estimated work load of 6 months,
                    > and I wanted to see how long it would take for a team of 3, 7, 10, and
                    > 15 to complete it. (I realize that's a completely fantasy-land task to
                    > go about doing.)
                    >
                    > When doing this, I was trying to come up with a communications
                    > overhead load factor to apply: something that simply helps illustrate
                    > the point that for each person you add, there's a certain amount of
                    > time added because the group of people grows and, thus, the time it
                    > takes to communicate as a team grows as well.
                    >
                    > I was sure I'd read something about this somewhere, but I couldn't
                    > find it. Almost every source I read mentioned this problem, but didn't
                    > give any rule-of-thumb type metrics to use.
                    >
                    > So, my question is, what are some good numbers to use to get a feeling
                    > for the extra time, due to communications overhead, that adding more
                    > team members creates?
                    >
                    > --
                    > http://www.drunkandretired.com
                    >
                    > To Post a message, send it to: scrumdevelopment@...
                    > To Unsubscribe, send a blank message to: scrumdevelopment-unsubscribe@...
                    > Yahoo! Groups Links
                    >
                    >
                    >
                    >
                    >


                    --
                    Jeff Sutherland, Ph.D.
                    CTO PatientKeeper Inc.
                    Certified ScrumMaster Practitioner and Inventor of the Agile Scrum Process
                    Microsoft Business Framework Advisory Council
                    Object Management Group/HL7 Liaison Committee
                    Co-Chair, HL7 Orders and Observations Technical Committee
                    Co-Investigator, Operating Room of the Future, Univ. of Maryland Medical System
                    617-947-7400 mobile
                    jeff.sutherland@...
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