The Flow Experiment

I put together a small simulation for the SPA Conference this year which seemed to go well, and which I re-ran at the London Limited WIP Society, and hope to run again. You can download the materials, and this is a short write-up of how it works so people can run it and experiment with it themselves.

Overview

The basic aim of the simulation is to solve maths problems. This idea was inspired by Simon Bennett and Mark Summers session The Incentive Trap which also uses maths as the problem domain. The solving of equations introduces variability into the exercise using some simple knowledge work which is hopefully more interesting and engaging than rolling dice.

The maths problems flow through the following value stream:

  • Options
  • Analysis
  • Solve
  • Check
  • Accepts
  • Done

The following roles are involved in the value stream:

  • Analyst
  • Solver
  • Checker
  • Accepter
  • Manager

The following scenarios are used to experiment with the flow:

  • Phase Driven
  • Time Boxed
  • Flow Based

Stages

Options

Each scenario starts with a portfolio of possible problems to solve, in the following format:

ID Operands Solution
1 3 25

In this example  we have an option to create an equation with 3 operands and a solution of 25.

Analysis

When an option is selected, it is transformed into an equation during analysis. Rather than expecting participants to come up with their own equations, which could result in trivial equations, a lookup is provided.  The equations in the lookup are in a different order to those in the portfolio so some effort is required!

Operands Solution Equation
3 25 3 * 7 + 4

Solve

The equations are then solved independently i.e. the solution is not available

Check

In order to check that the Solve stage produces a correct result, the equation is solved independently again.

Accept

Finally the two independent solutions are compared, along with the actual equation, to ensure it has been solved correctly

ID Operands Solution Equation
1 3 25 3 * 7 + 4

Done

When the correct equation has been independently solved correctly twice, then the problem can be considered Done.

Roles

Analyst

The analyst selects the options from the portfolio, matches them against the available equations, and writes them onto index cards. Each index card should contain the option ID and the equation as follows:

analyst

Solver

The solver takes each index card with an equation on it, and solves it. Any intermediate calculations should be written on a separate sheet, and calculators should not be used (although someone who did use a calculator at SPA didn’t seem to gain any advantage!) The answer is to be written on the back of the back of the index card, to the left side, and covered with a small post-it so that is hidden and can’t be copied.

solver

Checker

The checker also takes each index card with an equation on it, and solves it. Again, any intermediate calculations should be written on a separate sheet, and calculators should not be used. this time, the answer is to be written on the back of the back of the index card, to the right side, and again covered with a small post-it so that is hidden.

checker

Accepter

The accepter takes the index card and confirms whether the ID and equation match correctly, and that the two answers are both the same and correct. The they are, the the problem is Done, otherwise they reject it. Each scenario will handle rejection differently.

Manager

The managers job is to keep time, ensure the process is being followed and capture metrics. Every 30 seconds they should count how many of the maths problems are in each stage of the value stream and record it on a worksheet. It is these numbers which can be fed into a spreadsheet to generate a Cumulative Flow Diagram to visualise the flow.

manager

Scenarios

Each scenario is 5 minutes each.

Phase Driven

For a phase driven approach, the team should initially plan how many of the set of options they think that they can complete in the 5 minutes available. Then all the selected options are worked on phase by phase. Thus they are all analysed, then all handed over to be solved, then all handed over to be checked, and finally all handed over to be accepted. Any rejected work can only be moved back to the beginning once everything else has been accepted as Done.

Time Boxed

For the time boxed approach, the team should plan how many of the set of options they think that they can complete in the 1st of the 5 minutes. Those options are then worked on by the team individually. Specialism still applies, but once a problem has been analysed, it can move to be solved, check and analysed without waiting for the whole batch. At the end of the 1 minute time-box, the team should stop, review and re-plan the next minute, deciding how many problems to work on next. This is repeated until the 5 minutes are up i.e. there are 5 x 1 minutes time boxes. Any rejected work can be passed back immediately.

Flow Based

For the flow based approach, the team should pick 1 problem at a time to solve. As with the time boxed scenario, specialism still applies, so once a problem has been analysed, it can move to be solved, check and analysed. However, there should only be one problem in each stage of the value stream at a time, thus creating a pull system. Any rejected work can be passed back immediately (which may result in the WIP limits being broken), or the accepter can pull in the appropriate role to resolve the issue.

Results

The metrics from the managers worksheets can be fed into an excel spreadsheet (included in the download package) to generate CFD diagrams. Here are 3 from one of the teams at SPA.

Phase Driven

image

Time Boxed

image

Flow Based

image

Variations

There are a number of variations I’d like to try.

  • One of the things I’ve noticed is that the maths problems may be just a little bit too difficult for some teams, and the take too long sometimes to get any really useful results. One option would be to extend the time for each scenario to 10 minutes to allow more time. I wonder whether this could make it less snappy though.
  • The time-boxed scenario never really plays out how I envisaged it. This is partly down to the short time frames. Stopping, reviewing and replanning every minute doesn’t seem right – especially when you can only manage 1 problem in a minute! What i was trying to show was the small-batching nature a time-box can have. One way round this is to explicitly create the batches in a similar way to the Penny Game.
  • Some people don’t like the mental exercise involved in the maths! Katherine Kirk described a variation to me where the teams used a “Pictionary” workflow instead. Options –> Describing –> Drawing –> Guessing –> Checking –> Done
  • Its quite likely that the Flow scenario comes out “best” because its the last one. It would be interesting to run the scenarios in different orders to see what impact that had. Especially if there are 3 or more teams so that each team can start with a different scenario. This would possibly be more complicated to run, but with enough facilitation could be done.

Feel free to download the pack, which contains:

  • Handouts – PDFs of the options, analysis and accepter worksheets for each scenario
  • Spreadsheets – one with all the details used to create the worksheets, and one to be used to create the CFDs
  • Powerpoint – slides with simple instructions for running the experiment

All I ask is that you let me know how you got on, and what variations you come up with. Here are the SPA results and LWS results.

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What is Cadence?

Mark Stringer gave me some good feedback recently, that I clearly hadn’t described what I meant be Cadence at the recent miniSPA conference. In order to try and correct that, I thought I’d try and clarify with a blog post that it not simply variable length iterations.

The purpose of a cadence is to establish a reliable and dependable capability which demonstrates a predictable capacity. Cadence gives some confidence in the upcoming work when we are triggering rather than scheduling work.

Time-boxing is one specialised form of cadence. It’s like a metronome, giving a single tick. All the main process events are based around this single tick, as shown below where the dotted vertical lines represent the Sprint boundaries. In this example, the unit of work is a User Story, and User Stories should be small enough to be scheduled into a Sprint, and subsequently completed in the same Sprint. Stories in Progress are limited to two, as a good Scrum team might, but Stories don’t always fit exactly into a Sprint. Note also, that while releases can happen each Sprint, User Stories are only potentially shippable product increments.

Sprint

Kanban on the other hand has a cadence which is more like a drummer. The rhythm is more complex than the single tick of a metronome, and can be more varied, as shown below. In this example, the unit of work is a Minimal Marketable Feature, which while needing to be as small as possible, is not constrained be being required to fit into a schedule. Instead, an MMF is able to flow over a number of process events while it delivers some releasable value. Planning, reviewing, retrospection and releasing all still happen regularly, but they are de-coupled. They can happen independently, at differing rates, which may provide more freedom in creating a natural process which enables the team.

Kanban

A cadence is usually ‘harmonic’, in that there is a neat overlap between the different rhythms, as in this example. However, it does not have to be. A look at some definitions of cadence can show why. These are some favourites I picked off dictionary.com

  • In music, the ending of a phrase, perceived as a rhythmic or melodic articulation or a harmonic change or all of these; in a larger sense, a cadence may be a demarcation of a half-phrase, of a section of music, or of an entire movement
  • Music. A progression of chords moving to a harmonic close, point of rest, or sense of resolution.
  • The flow or rhythm of events, esp. the pattern in which something is experienced: the frenetic cadence of modern life.

Thus cadence is what gives a team a feeling of demarcation, progression, resolution or flow. A pattern which allows the team to know what they are doing and when it will be done. For very small, or mature teams, this cadence could by complex, arrhythmic or syncopated. However, it is enough to allow a team to make reliable commitments because recognising their cadence allows them to understand their capability or capacity.

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Anxiety or Boredom Driven Process Improvement?

At the SPA conference recently, Joseph Pelrine talked about “Flow: The Psychology of Optimal Experience” by Mihalyi Czikszentmihalyi. The ideas behind this struck a chord with me as a way of describing something I originally said when discussing whether kanban is only suitable for mature teams. That is that rather than focusing on being Agile which may (and should) lead to being successful, Kanban focuses on becoming successful, which may lead to being Agile.

Mihalyi Czikszentmihalyi describes the state of Flow as having a balance between ability, and the skills required for a piece of work. If some work requires more skill than a person has ability, then they are in a state of Anxiety. If a person has more ability than the skills required for a some work then they are in a state of Boredom. Applying this to Process Improvement, we want to move teams up the Flow Zone so that skills required and ability increase equally.

Flow1

Increasing Skills and Ability equally at the same time is unlikely, so in practice there are two routes to move up the Flow Zone. The first is what I am dubbing “Anxiety Driven Process Improvement”. Move a team into a state of Anxiety such that they need to improve their skills to cope. I assert that this is the approach that makes time-box based method so effective. Time-boxing forces teams into a place where they need to improve their skills in order to deliver working software every few weeks. Many teams push back, and a common approach to this is to make the time-box shorter to emphasis the point! The other route is to do “Boredom Driven Process Improvement”.  Highlight to the teams where they need to improve their ability, and allow and support them in doing so such that they are able to taken on work requiring more skill. I further assert that this is the approach that kanban systems take. Visualising queues and work in progress in order expose the bottleneck where the ability needs improving.

Flow2

This might sound like I am suggesting the time-boxing and kanban are mutually exclusive approaches. That isn’t the case – I have already said that! Instead, I just find it an interesting angle to look at a different dynamic between two approaches.

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Kanban and Time-boxes

I had a brief exchange of tweets with Ron Jeffries, Keith Braithwaite and James Shore after the Miami Lean and Kanban Conference ended regarded Kanban and its compatibility with XP and time-boxes. Unfortunately I wasn’t able to follow up immediately, due to an urgent (and eventful) trip to South Beach 🙂 Rather than try and follow up late on twitter, I’ve decided to post my thoughts here to try and clarify my ideas.

The discussion started following a tweet about Kanban being easier to introduce than Scrum. This seemed to be a common theme at the conference, with several experience reports confirming what I have already written about whether Kanban is only suitable for mature teams. This led to the question of how much change (or not) a Kanban approach requires, which is where I jumped in.

A kanban approach introduces tools to visualise and measure queues and work in progress. While this is a change in process measurement, it doesn’t change the process itself. However, having highlighted the existence of queues and work in progress, it becomes easier for the process to be changed to specifically fix the issues highlighted. Thus a Kanban system sets a team up to begin continuous improvement. Time-boxing, used by XP and Scrum, is one way to manage queues and WIP, which is why they can be such effective processes, and why shorter time-boxes are becoming more popular. There are other ways of managing queues and work in progress, however, and thus Kanban is agnostic to time-boxing. This does not mean that XP is Kanban system however, because XP implicitly, rather than explicitly, manage the queues and work in progress.

Further benefits of time-boxing are the focus that they give, particularly given the finite or limited resources (i.e. people) within a team. Time-boxes give this focus not only by limiting the work-in progress, but also by setting the end of time-box as an SLA for when the work will be completed. Again, Kanban doesn’t lose these benefits, but provides for alternate means to limit work in progress and set SLAs.

To summarise, I believe that a Kanban approach is compatible with XP and Scrum in that it has a focus on managing queues and limiting work in progress, but also introduces alternate ways to achieve these goals which can be used alongside the XP and Scrum tools such as User Stories, TDD and Retrospectives.

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