Mura 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.

Mura is the Japanese word for “unevenness, irregularity, lack of uniformity”. It describes “feast and famine” cycles of work when some periods are significantly busier than others. Mura is a barrier to flow.

What is Mura?

Unevenness occurs in an agile team when there is a wide variety of sizes of Product Backlog items. The larger the item, the greater the inbuilt and hidden variability. Large items:

  • Are slow to deliver to Done.
  • Slows the rest of the team down in delivery of other items that are in-progress.
  • Often have lots of “waiting” time and then “hurry” time for team members.

Why does Mura occur?

  • Uneven customer demand: The customer is always right, but what does the customer want? For early-stage startups, defining customer requirements and keeping track of them as they change can be a nightmare. Planning too far ahead can lead to wastes if customer needs have changed by the time the project is delivered.
  • Uneven workload: Sometimes your team is stretched to breaking point. Other times, team members don’t have enough to occupy their time. This often follows uneven customer demand but also goes hand in hand with large batch delivery sizes.
  • Irregular working rhythm: Irregular working rhythm happens when tasks pass through your process erratically. Work in progress accumulates and bottlenecks form in some stages of the process, causing an interruption to the flow of work. Irregular working rhythms lead to high variability in throughput and cycle time, leading to a less predictable process.

Things to try

Unevenness often can be eliminated by teams through level scheduling and careful attention to the pace of work and the size of Backlog items.

#NoEstimates

The “no estimates” movement recommend slicing items into their smallest, consistent size. That is, slicing every Backlog Items into “Small” by the time it comes to a Sprint.

Kanban

Kanban focuses on increasing workflow efficiency and helping teams to achieve continuous improvement. It uses several powerful tools for identifying areas of Mura within your process and working to eliminate them. 

1. Understand flow by visualising the work

Visualisation is one of the key principles of the methodology – a picture is worth a thousand words. The Kanban board makes bottlenecks immediately apparent, and changes in the gradient of the cumulative flow diagram are a warning sign of problems brewing and increases in Mura. You can also use charts such as the cycle time scatterplot and throughput histogram to assess your level of Mura over time – more regular and consistent results means your efforts to reduce Mura are working.

2. Long-term directions, short-term details

Uneven and changing customer demands lead to Mura. Developing a Kanban roadmap to set your goals and directions, rather than planning in detail what tasks you will be working on six months from now. In the short-term, Product Managers and other stakeholders can then translate these goals into work items, prioritise them accordingly and feed them into the backlog. This lets your team pull tasks into the workflow at a steady pace. The Kanban Method suggests an approach to Backlog management that reduces the effort of maintaining your backlog and helps teams improve self-management.

3. Implement work in progress (WIP) limits and “pull” policies

Accumulation of lots of work in progress in any one process stage inevitably causes unevenness. Kanban work in progress limits are used to avoid this – new backlog items cannot be pulled into a process stage before an outstanding task has moved to the next stage. This can help you maintain a steady flow of tasks. Make sure to have explicit pull policies to ensure tasks enter and leave process stages in the same order, or your cycle times will become more variable.

4. Find your constraints

Irregular working rhythms are a major cause of Mura. As mentioned above, this frequently occurs because of slow process stages affecting up and downstream stages. The theory of constraints states that the flow of a process can be no greater than its slowest stage – its constraint. Improving the constraint improves the flow, making the working rhythm smoother and more consistent.

There is no magic bullet to eliminate Mura from your workflow once and for all. There are hundreds of factors that can cause unevenness within your process, both within and out of your control. Nevertheless, making these incremental, iterative changes will have a cumulative effect – a more predictable and profitable process.

References

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

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