Aging Work in Kanban: Tasks that Linger in Your Flow
One of the most quoted sayings in Kanban translates to: ”stop starting and start finishing.” This principle of not starting new work until the task at hand is completed, also called a Kanban pull system, is one of the central ideologies in Kanban.
A well-implemented pull system increases workflow efficiency and prevents teams from overcapacity and burnout. Essentially, tasks are moving forward if and only if a pull signal has been triggered to indicate a new slot has freed up.
However, without explicit pull policies in different process states and when the tasks have the same class of service, the team would instinctively pull the least-time-consuming work first. This, in turn, creates a breeding ground for delays, as heavier tasks which are constantly being put off start lingering in progress states.
Causes and Effects of Aging Work
Тhere are plenty of reasons causing tasks to get stuck in your workflow. Internal and external blockers, neglected maintenance tasks, unclear requirements, delayed business feedback – these are a handful of causes behind delayed work in progress.
Being unable to track how much time your tasks spend in your process states is a major problem, which, if left concealed, can lead to poor decision-making, breach of commitments, and distrust of your team’s capabilities to deliver results successfully.
Additionally, leaving incomplete tasks in the workflow for too long drastically increases your average cycle time. This concept of flow debt makes your system unstable and unpredictable, as it carries a risk of reduced forecasting accuracy. And ineffective forecasting will hinder your ability to predict delivery times for both single work items and entire projects.
These are all deeply adverse effects and the following question arises – how do you avoid work in progress from being delayed?
Flagging Due Tasks with Aging Chart
The first step is to take a look at the current state of your WIP tasks. Kanban analytics tools such as the Aging Chart offer a detailed overview of where your tasks are in your process and how much time every task spends in each process state. The horizontal axis outlines all workflow states while the vertical axis shows how many days a certain task has spent in the workflow. The higher the dot, the longer the task is taking to complete,and the higher the chances of a delay.
The Aging Chart builds over your past data to provide you with a solid guideline on how your current tasks are progressing. The percentile lines that run alongside the vertical axis indicate the percentage of tasks that were previously completed. For example, if a task is climbing past the 50th percentile line, it means it is already taking more time to complete than half of your previous tasks. You can monitor the progress of each task in real-time to spot red flags instantly and prevent slower tasks from becoming bottlenecks.
Moreover, you can leverage the data from your Aging Chart to propose business commitments to clients and stakeholders. In Kanban, every commitment comes with its probability of being met. Taking the image from above for an example, you could say with a 70% certainty your team can handle any task in less than 11 days. Equally, you could commit to delivering a task within 7 days but there’s a 50/50 chance of achieving that goal.
With Nave, you can use the Aging Chart within your favorite project management tool to boost your productivity and improve workflow efficiency.
Effective Ways to Prevent Delays
Limiting the amount of WIP only partially reduces the risks to your workflow. To truly maintain a healthy flow, you need to limit the age of your individual WIP tasks.
A simple, yet effective method is to introduce a new policy where a task becomes expedite if it’s approaching the commitment. If you’ve agreed to deliver a task within 11 days with a 70% certainty then the task becomes expedite class of service (high priority) once it crosses the 50th percentile. Essentially, what you’re saying is: ”50% of our tasks have taken longer than this one to complete. Let’s focus on it in order to fulfill our commitment.”
Another useful practice is to set a due date for each task that is pulled into your process. If you decided to work with a commitment of 14 days, introduce a policy of setting a due date – two weeks from the day the task has been pulled in progress. It will be easier to pay attention to the tasks in your Kanban board whose due date is approaching and adhere to that commitment.
Finally, consider adopting an explicit policy of pulling the tasks across the process in the same order they arrive in. In other words, the oldest task should be the first to leave the process. We managed to reduce our cycle times by 250% adopting this approach.
By implementing all of these practices, you are effectively preventing your work in progress from aging, and by doing so ultimately reducing the risks associated with this neglect. Start monitoring and actively managing your work in progress using these approaches and strive to prevent your tasks from falling into oblivion ever again.
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.