Agile PM Process Grid-2.9 Work-in-Process Limits (1)


In John Stenbeck’s book “PMI-ACP and Certified Scrum Professional Exam Prep and Desk Reference”, he creates an “agile project management process grid” which describes 87 processes used in agile project management.   These processes are divided into five process groups (Initiate, Plan, Iterate, Control, and Close), which are analogous to the five process groups in traditional project management, and seven knowledge areas which can be mapped, more or less, onto the ten knowledge areas in traditional project management.

Work-in-Process (WIP) is a concept borrowed, as much of agile methodology is, from Lean thinking to improve the value stream of product development.   The basic idea is that a project is a type of WIP because the business cannot realize value from user stories in process, but ONLY from potentially shippable increments of the solution.

In the previous post discussing cycle time, it was noted that the business can derive value sooner if the cycle time is shortened, particularly through process improvements external to the time.

The use of WIP limits improves the team’s workflow by controlling the amount of WIP at each step in the process.   This helps the team overcome perceived impediments to completely finishing each story.   The helpful analogy that John Stenbeck gives is the same way stop lights on freeway on-ramps prevent rush hour gridlock by limiting the number of cars entering the system depending on how many cars are already in the system.

In agile terms, WIP limits limit the number of stories being actively worked on by the team at any single point in time.    This actually courses more stories to be completed.

How do you measure WIP?   It would seem to be complicated because it is a moving variable, like the traffic moving on the freeway in the analogy given above.   The best way to measure and manage WIP is to

  1. check the story board a few times per day and count how many stories are in the queue:  this will be the current WIP level.
  2. Take the average of the measurements after a few days and give some sort of buffer for comfort.
  3. Estimate the maximum and set it as the initial limit or starting Maximum Allowable WIP.
  4. Make periodic reductions in the limit and measure the impact on productivity.
  5. The most desirable WIP limit will emerge rather quickly.

This shows you reference point for WIP measurement.

How do you reduce WIP once you’ve measured it?   That will be the subject of the next post.

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