Muri and Waste

Advanced

difficulty

Stage 5

Agile IQ® Level

Waste & Flow

Practices

Lean

Frameworks

Introduction

MUDA, MURA, MURI are three terms often used together in the Toyota Production System (and called the Three Ms) that collectively describe wasteful practices to be eliminated.

Muri is the Japanese term for “overburden, unreasonableness, beyond one’s power”. It means pushing your team beyond their capacity. While this is obviously a problem, how does it relate to waste?

What is Muri?

Muri is deeply intertwined with the other two types of waste, Muda and Mura. Mura (unevenness) leads to teams alternating between being overloaded with work and having nothing to do.

Many Mudas – Overproduction, Overprocessing, Motion, and Transportation – unnecessarily increase the workload for teams. Muri can also cause Muda. For example, a team rushing to complete a deadline without enough time to do it properly will cause the defects and unintended re-work due to problems in quality.

Why does Muri occur?

  • Unreasonable demands: The number one cause of Muri is excessive, unreasonable, and unnecessary demands upon your team. Pushing more work onto a team does not automatically translate to more work delivered – instead, you have increased stress, more mistakes, and growing levels of work in progress.
  • Poor allocation of tasks/people: Too much work is an obvious cause of Muri, but badly allocated work can equally lead to overburden. When the right amount of work is given to the team without considering the dependencies of the tasks, bottlenecks occur. This is especially common in highly specialised teams, where some tasks can only be carried out by one or two specific people.
  • Excessive Muda and Mura: As we mentioned above, the three wastes are interlinked and affect one another. Producing things that a customer hasn’t asked for are frequent causes of unnecessary work for teams. It eats into the time that could be spent adding value. Unevenness in a team’s process is proportionally related to the levels of overburden and waste.

Things to try

The key to reducing Muri in a team’s process is to ensure demands are brought in line with the team’s capacity.

When demand (load) and capacity are as close to equal as possible, workflow becomes smooth, streamlined, and efficient. Streamlined workflow leads to consistent results and improved throughput.

Reduce Mura and Muda

Reducing unevenness in your process will cause a parallel reduction in Muri and should be made a high priority. Visualize your entire process step by step – what steps cause unnecessary work for your team? Pay particular attention to the Overprocessing, Overproduction, Transportation, and Motion Mudas.

Overprocessing and Overproduction can be managed by properly defining expected results and ensuring these are clearly communicated to your team. As for Motion and Transportation, look for ways to free your team members from administrative burdens. Can any repetitive steps of the workflow be automated? Is there a more efficient “trigger” for the next stage of the process (e.g. automatic Trello notification instead of manually sending an email)?

Switch to a pull system

When work is pushed onto your team without considering their capacity, Muri is bound to happen. Switching to a pull system such as Kanban can help you ensure that your team only pulls new tasks into the workflow when they have the capacity to do so.

Adopt and refine your use of Kanban

Muri and Kanban

Kanban is designed to make workflows more productive and efficient. Here are some Kanban practices that can help you keep Muri at manageable levels.

Setting appropriate WIP limits

One method of stopping overburden in its tracks is to set strict limits on the amount of work in progress. New tasks are not allowed to enter a stage in the process until an outstanding task has been completed. It’s important to pick the right WIP limit for each stage of your process. The best limit is low enough to make sure all tasks are being worked on, and high enough to keep your whole team busy at all times.

Make policies explicit

Use explicit policies and Kanban rules to prevent forming bottlenecks and stalled work. In specialized teams, splitting the workflow into swimlanes for each specialist or specialist subgroup gives you clear visibility on the workload of each team member. Each swimlane requires its own WIP limit.

Find and eliminate bottlenecks

Bottlenecks signal that some part of your process is overburdened. Find your bottlenecks by visualising your process in a Kanban board and performing deep analysis over it using a cumulative flow diagram.

Track results

The ultimate goal of reducing waste is to improve productivity. Kanban suggests several productivity metrics that you can use to observe how the changes you are making are affecting your process. The positive results from making continuous effort to reduce Muri and the other wastes should show in your throughput and cycle time figures over time. Track how these figures are changing using:

  • Cycle time scatterplot.
  • Cycle time histogram.
  • Throughput run chart.
  • Throughput histogram.

References

1. Siderova, S. (2019) Lean Manufacturing Wastes: Muri

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