Lean Manufacturing Wastes: Muri
Reducing waste allows you to achieve more with your team, streamlining your processes, and maximizing your profits. In our previous articles, we looked at two forms of Lean Manufacturing Wastes: Muda (waste) and Mura (unevenness), when they are likely to appear, and what steps to take to reduce them.
As part of their continuous improvement initiative, businesses generally first work on wiping out the 7 Mudas (Defects, Overprocessing, Waiting, Transportation, Inventory, Motion, Overproduction) and keeping Mura down. This is a great start, but for a truly efficient process, it’s crucial to understand how all three types of waste interact and affect each other. In this article, we’ll take a look at the third waste, Muri.
What is Muri?
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?
Muri is deeply intertwined with the other two types of waste, Muda and Mura. Mura (unevenness) leads to your team alternating between being overloaded with work and having nothing to do. Many Mudas – Overproduction, Overprocessing, Motion, and Transportation – unnecessarily increase the workload for your team. 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 waste.
Muri in Knowledge Work
Like the other two wastes, Muda and Mura, Muri originates from the Toyota Production System, the original basis for Kanban and Lean Manufacturing. Whereas some of the Lean Manufacturing concepts need to be updated for the knowledge work environment, we’re sure you can already think of some areas in your process where overburden is causing issues. Let’s take a look at some common causes of Muri:
- 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 are sure to happen. This is especially common in highly specialized 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. The Overprocessing and Overproduction Mudas are frequent causes of unnecessary work for your team, eating into time that could be spent adding value. Unevenness in your process is proportionally related to the levels of overburden and waste.
Overburden leads to a stressed team and sloppy results. Simply having team members work 30% more hours will not lead to a 30% increase in throughput. Increasing workload very quickly leads to diminishing returns, and at a certain point, a stressed and tired team will end up spending more time correcting their mistakes than delivering value.
How to Reduce Muri
The key to reducing Muri in your process is to ensure demands on your team are brought in line with your team capacity. When demand and capacity are as close to equal as possible, your workflow becomes smooth, streamlined, and efficient. Streamlined workflows lead to consistent results being delivered faster.
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.
Muri and Kanban
The Kanban method 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 visualizing your process in a Kanban board and performing deep analysis over it using the 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. We recommend tracking how these figures are changing using the Cycle time scatterplot, Cycle time histogram, Throughput run chart, and Throughput histogram.
Muri not only makes for an inefficient and wasteful process, but it also hurts your team. Stressed, tired, and overworked team members find it harder to make smart decisions, take initiative, and deliver high-quality work. Eliminating Muri will reduce the waste in your process and make it more efficient while raising team morale. Keeping overburden waste to a minimum gives your team space to breathe and consistently deliver quality results.
Which areas of your process suffer most from Muri? What steps did you take to reduce it? Did reducing Muda and Mura also reduce Muri for your team? Tell us about your experience in the comments!
Meet the Author
Sonya Siderova is a passionate product manager and a driving force behind Nave, a Kanban analytics suite that helps teams improve their delivery speed through data-driven decision making. When she's not catering to her two little ones, you might find Sonya absorbed in a good heavyweight boxing match or behind a screen crafting a new blog post.