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Re: [XP] New practice: Slack

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  • Paul Beckford
    ... Hi Jeff, I agree. I think this is the point I m trying to make. Open loop (no feedback from customer) we cannot predict. Software development is chaotic,
    Message 1 of 110 , Jan 2, 2006
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      jeffadams78 wrote:

      >I realize I'm new here but I think I might see something not mentioned
      >before.
      >
      >Perhaps the key is the amount of customer involvement?
      >
      >If you have a customer there by your side every day (or maybe every
      >week) then worrying about slack doesn't seem super-important. If you
      >start running behind, the customer can immediately tell you which task
      >to drop. If you finish ahead, the customer can tell you the next
      >tasks to add on.
      >
      >However if you see the customer more rarely, slack becomes important.
      > If you know it will be a month before you see the customer again, you
      >(and the customer) should know here is the list of tasks that we are
      >committed to definitely doing. Let's say 75 tasks. We think we can
      >probably do 100, but we're only committing to 75 because of the risk
      >of unforeseen problems. The other 25 will be called slack; the
      >customer specifies some tasks that are important, but OK if they don't
      >get delivered. That way you don't have either of the following scenarios:
      >
      >You see the customer after a month, and you have to tell them "Sorry
      >we only finished 75 out of the 100 tasks we committed to."
      >
      >Or, you see the customer after a month and you say "Well we finished
      >all 75 tasks at the end of week three, so we spent a week surfing in
      >the bahamas (or having to pick tasks at random rather than with
      >customer imput)."
      >
      >In fact (correct me if I'm wrong) you'd probably in this case have
      >more than 25 tasks as slack, just on the off-chance that you get ahead
      >of schedule.
      >
      >Jeff Adams
      >
      >
      >
      >
      Hi Jeff,

      I agree. I think this is the point I'm trying to make. Open loop (no
      feedback from customer) we cannot predict. Software development is
      chaotic, complex and unpredictable, hence the experience of the last
      20-30 years and all those failed waterfall projects. But closed loop
      (with customer feedback) then predictablity increases greatly.

      So the question then is, how much feedback do you need? The smaller the
      iteration size then the less the delta of error but the greater the
      overhead. The larger the iteration size then the greater the delta and
      the lower the overhead.

      As I've understood it from following this thread (I do not have a copy
      of XPE2E), Slack is about increasing the certainty of the outcome of a
      single iteration (not a release). So why would you want to do this?

      For the specific problem you describe I can see two alternative
      solutions to Slack:

      1. Call the customer mid-iteration and tell him that we need about
      another 25 stories, shall we just pull them off the (prioritised) backlog?
      2. Reduce the iteration size untill the team gets better at predictions
      (which could take 3-4 iterations).

      I'm looking at this from a SCRUM perspective. As I understand it the
      inherent risk to the "release" can safely be managed using a burn down
      chart. No need for Slack.

      Here is a link to an article that I think is saying the same thing:

      http://alistair.cockburn.us/crystal/articles/evabc/earnedvalueandburncharts.htm

      Paul.

      >
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    • Paul Beckford
      ... Hi Victor, I totally agree. I am a European too (I live and work in the UK), and I ve also worked in the States, and there is a cultural difference (by and
      Message 110 of 110 , Feb 12, 2006
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        Victor wrote:

        > I think this is a serious social
        >issue that needs to be confronted by society as a whole at the educational
        >level. Honesty can be tough to maintain in an environment that values
        >denial and unrealistic expectations, but in final account it's the best
        >policy.
        >
        >Victor
        >
        >
        Hi Victor,

        I totally agree. I am a European too (I live and work in the UK), and
        I've also worked in the States, and there is a cultural difference (by
        and large I find both the UK and the US very similiar though). I think
        it has something to do with the perception of science in the west and
        the role of the scientific expert. Earlier in this thread (way back)
        someone made a similar point about Doctors in the west not being able to
        say that they don't know, and presumeably experiencing emotions of guilt
        when they truly do not know.

        In software I think it is about organisational culture, and I have
        experienced cultural change by simply telling people I do not know. At
        first they are shocked, but once you encourage them to take the second
        person perspective (seeing things from your point of view), they quickly
        realise that this is the only honest answer and they respect you for it.

        With regards to the long term, many people in the west no longer trust
        Doctors and are increasingly looking to "alternative medicine". In
        China this seems to be less of an issue, as Chinese doctors are more
        willing to use approaches that aren't strictly "scientific". Maybe this
        is a tacit admission that as Doctors they do not always know the
        precise casual basis for illness and maybe as a consequence of this
        tacit admission people in China tend to trust them more.

        Just a thought.

        Paul.

        >=========================================================
        >----- Original Message -----
        >From: "Kent Beck" <kentb@...>
        >To: <extremeprogramming@yahoogroups.com>
        >Sent: Wednesday, February 08, 2006 1:48 PM
        >Subject: RE: Cultural difference was ->(Re: [XP] Re: New practice: Slack)
        >
        >
        >
        >
        >>David,
        >>
        >>The European cultures I have worked in do seem to be willing to make slack
        >>
        >>
        >a
        >
        >
        >>more visible part of the rhythms of work. Whether it is frequent espresso
        >>breaks or one-contiguous-month vacations in the summer, there seems to be
        >>more of a understanding that there is more to life than work and that work
        >>goes better when we acknowledge that. I have also seen significant erosion
        >>of this understanding in recent years, which makes paying attention to the
        >>value of slack increasingly important.
        >>
        >>As far as trust and promises are concern, if I want my children to trust
        >>
        >>
        >me,
        >
        >
        >>I will say, "I will be home at 8:30" and sometimes be early instead of
        >>saying, "I will be home at 8:00" and often being late. Whether I have a
        >>
        >>
        >good
        >
        >
        >>excuse ("traffic, you know") doesn't matter to a kid near as much as
        >>
        >>
        >knowing
        >
        >
        >>whether they can count on me.
        >>
        >>That said, I still make too many professional commitments based on what I
        >>think people want to hear and end up missing them. However, even when I
        >>
        >>
        >make
        >
        >
        >>promises I secretly think I can't meet, the big issue for me is time
        >>management. If I improved my ability to focus and prioritize I would be
        >>
        >>
        >able
        >
        >
        >>to make and meet promises with much less slack than I currently use.
        >>
        >>Sincerely yours,
        >>
        >>Kent Beck
        >>Three Rivers Institute
        >>
        >>
        >>
        >>>-----Original Message-----
        >>>From: extremeprogramming@yahoogroups.com
        >>>[mailto:extremeprogramming@yahoogroups.com] On Behalf Of David H.
        >>>Sent: Tuesday, February 07, 2006 5:45 AM
        >>>To: extremeprogramming@yahoogroups.com
        >>>Subject: Cultural difference was ->(Re: [XP] Re: New practice: Slack)
        >>>
        >>>Kent Beck wrote:
        >>>
        >>>
        >>>>David,
        >>>>
        >>>>
        >>>>
        >>>Hello Kent.
        >>>
        >>>First of all please accept my apologies for answering so belatedly.
        >>>
        >>>
        >>>
        >>>>I think software developers and managers have always
        >>>>
        >>>>
        >>>included lots of slack
        >>>
        >>>
        >>>>in their schedules. We just didn't talk about it. The
        >>>>
        >>>>
        >>>client or boss was
        >>>
        >>>
        >>>>"supposed" to think that we were working as hard as we
        >>>>
        >>>>
        >>>could 150% of the
        >>>
        >>>
        >>>>time, taking only Sunday mornings off. What happens if we
        >>>>
        >>>>
        >>>admit we are
        >>>
        >>>
        >>>>human? We take coffee breaks and time to think and look out
        >>>>
        >>>>
        >>>the window at
        >>>
        >>>
        >>>>the weather?
        >>>>
        >>>>
        >>>>
        >>>That is something, I as European, cannot quite understand.
        >>>Yes, there is peer
        >>>pressure in our countries as well, but the chances that you
        >>>get fired because
        >>>you are not working "hard enough" are pretty slim. This is
        >>>basically caused
        >>>due to our employment laws which are usually in favour of the
        >>>employee and not
        >>>the employer. As such I do not have to worry too much about
        >>>my financial
        >>>freedom or my career as long as I do pay attention to what I am doing.
        >>>
        >>>I wonder how that is influenced by the fact that I recall,
        >>>for my visits in
        >>>the USA, that this is not the case in most companies over
        >>>there. Everyone
        >>>seems very concerned how their doing is perceived by the
        >>>bosses, always aware
        >>>that they _could_ be out of work by tomorrow.
        >>>
        >>>
        >>><snip>
        >>>
        >>>
        >>>
        >>>
        >>>>What I have found for myself is that when I am open with my
        >>>>
        >>>>
        >>>customers about
        >>>
        >>>
        >>>>the process I use to make promises I feel exposed. I have
        >>>>
        >>>>
        >>>no information in
        >>>
        >>>
        >>>>reserve with which to protect myself if I break my promise.
        >>>>
        >>>>
        >>>However, when I
        >>>
        >>>
        >>>>make transparent promises, I focus harder and don't waste
        >>>>
        >>>>
        >>>time keeping track
        >>>
        >>>
        >>>>of what I am holding back, so I get more done. It works for
        >>>>
        >>>>
        >>>me, even though
        >>>
        >>>
        >>>>it doesn't always feel good yet.
        >>>>
        >>>>
        >>>>
        >>>Is this not also a matter of trust. Making promises that are
        >>>not transparent
        >>>or based on assumptions will most likely cause a more than
        >>>negative reaction
        >>>in the one you promised them too when you cannot fulfill
        >>>them. I like to think
        >>>of this like a parent promising something to their child.
        >>>When I am honest
        >>>about the possibility of failure, the child usually will
        >>>accept that when I
        >>>cannot fulfill my promise. Very similar to saying:
        >>>
        >>>I will be home by 8pm versus I will try to be home at 8pm,
        >>>but I might not be
        >>>able to be here, because the traffic will be bad tonight.
        >>>
        >>>I know that most customers will expect you to say "I will be
        >>>home by 8pm", so
        >>>how do you get out of that dilemma?
        >>>
        >>>
        >>
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