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.
Muda is the Japanese word for waste. One way to describe a wasteful process or activity is “something that adds no value” to the customer. Ultimately, while a team might find an activity useful and valuable, if those activities don’t add value to the customer, either through impact or outcome, it is likely to be a form of Muda and a target for removal.
In some cases, determining what adds value and what does not is not so cut and dry. Business activities can be split into the three following categories:
In a manufacturing environment, this means the literal movement of raw material and stock from one place to another. Nevertheless, the concept still applies to knowledge work. Consider how a task moves from development to testing, or from writing to editing. What triggers the move from one state to the next?
Signing documents, reviews, sending emails – could any of these steps be made more efficient or even automated? E.g.: setting up Trello notifications to notify other collaborators rather than manually sending emails. Another source of transportation waste is tasks moving back and forth due to miscommunication, unclear requirements, or poor quality of execution.
Inventory is the accumulation of work in progress. It can also mean an accumulation of finished product that has not been sold or delivered to your customer yet. In Kanban processes, this primarily appears in the form of WIP items splitting your team’s focus and causing a bottleneck. Inventory build-up indicates that your flow is being hampered. This waste is reduced by adhering to “Just In Time” principles (i.e. at the last responsible moment) and only pulling a task through when your team has the capacity to work on it.
Whereas transportation focuses on unnecessary movement between stages of a process, motion waste seeks to reduce unnecessary movement within it. Making each motion as small and ergonomic as possible is crucial in a manufacturing setting. But how can you reduce motion in knowledge work? There are hundreds of wasted motions – manually inputting data, chains of emails, searching, and filing. Document management systems and business process automation are some methods used to reduce the waste of motion.
The Muda of waiting is easily the most obvious form of waste in a Kanban process. It frequently appears in two forms. First, tasks are idle because team members can’t handle all of the WIP. Secondly, tasks are queueing to enter the next process stage because there is not enough capacity to pull them through. Some methods to reduce waiting waste are making sure WIP limits are suitable for your team and establishing explicit Kanban rules and pull policies in your process.
This waste can negatively affect your business in multiple ways. Your customer may not need all of the product features developed – the effort spent on a high throughput is wasted! Overproduction equally ties up time, effort, and money that could be better spent on other value-adding activities, and leads to further waste by increasing Inventory/Work In Progress. Matching delivery to demand in timing as well as quantity is the core principle of Just in Time production.
Overdelivering can be seen as a virtue, but in most cases, your customer will not be happy to shoulder an extra cost or wait additional time. The overprocessing Muda often comes from defining the specification or scope with your client too loosely – team members strive to deliver 100% when your client might only need 75% to reach their goals. This often comes from a misunderstanding of why customers buy your product, and what looks better to the product owner might look worse to the customer if the necessary market research and customer satisfaction data aren’t present.
The Muda of defects has costs which increase proportionally to how long it takes for the defect to be noticed. A defect that makes it through to your final product leads to poor customer satisfaction. Other costs include redoing the work correctly. Reducing this waste requires testing and quality assessments at each stage of your process to ensure defects are caught immediately after they occur.
Agile teams strive to make processes more efficient and productive. All too frequently the human factor is overlooked. Your team members work on your process every single day – they will have many insights to contribute. Encouraging your team to give their input and help solve problems is a key part of Kaizen culture.
Kanban relies on the cumulative effect of multiple small changes. There will be hundreds of opportunities across your business to reduce waste a little bit at a time. However, to quantify the effect of a change, you must make sure you are accurately tracking your Kanban metrics. Rigorous measuring and analysis ensure you know which actions make the biggest difference to your customer satisfaction and your bottom line.
The key to reducing Muda in a team’s process is to understand how the team’s activities directly relate to the end product that is used by the customer.
Kanban and value stream mapping are key tools to understand Muda.
Kanban is designed to make workflows more productive and efficient. Here are some Kanban practices that can help you keep Muda at manageable levels.
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.
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.
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.
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 Muda and the other wastes should show in your throughput and cycle time figures over time. Track how these figures are changing using:
1. Siderova, S. (2019) Lean Manufacturing Wastes: Muda