Track your work in progress. Evaluate your average delivery times. Measure your process health.
The Cumulative Flow Diagram for Trello (CFD) consists of multiple colored bands, each of which corresponds to a list in your Trello board. The graph’s horizontal axis shows a timeline, while the vertical axis displays the number of tasks in your lists. The size of each colored area indicates the current number of work items on each list in Trello.
Strive to keep the number of tasks within the WIP limits for each list - by keeping the amount of work within the limits, you will help your team achieve a stable process.
On any given date, the graph shows the number of work items in each process state. You can also hover over the ‘Done’ area of the graph to track the accumulated number of tasks completed in the selected time frame.
On the Cumulative Flow Diagram for Trello, you can switch between 'process' and 'states' in your WIP tooltip to see your total WIP or the specific WIP in each list on your Trello board.
At any given point, the horizontal difference between the top and the bottom line of a CFD gives you your process's approximate average cycle time. It indicates how long it took on average for items to complete on the selected day.
By comparing the approximate average cycle time from your CFD with the exact average cycle time from your Cycle Time Histogram for Trello you can assess your process performance. You should be aiming to keep the two values roughly equal - this would mean that you’re maintaining a stable system.
The bottom line of the Cumulative Flow Diagram for Trello represents the ‘Done’ state of your process. By observing that line on the CFD, you can measure the amount of work your team has already delivered. The slope of that line between any two points is your average throughput between those two points. If your ‘Done’ area grows rapidly - this would mean that your team is productive and self-organized and delivers results in a consistent manner.
Keep an eye on the changing shape of your ‘Done’ gradient! The slower it grows, the longer your delivery times.
The top line of the graph represents the arrival rate of tasks while the bottom line shows their departures. These two lines illustrate the rates that you start new work and finish outstanding work.
To maintain a stable system, it’s key that you monitor how these lines move over time. Keeping your WIP as consistent as possible is a prerequisite to achieving a predictable workflow. If WIP is consistent, the arrival rate and departure rate lines will grow in sync and the distance between them will stay equal.
The ‘Arrival and Throughput Rates’ widget on the Cumulative Flow Diagram for Trello enables you to track any changes to your arrival and throughput rates over a selected time frame. Ideally, you should see these lines overlap with each other.
If the arrival line goes up, this means that you’re starting work faster than you finish it. This means that your team is working on more tasks than they are able to handle at a time. This trend could result in increased cycle times, reduced team efficiency and potential delays.
The Cumulative Flow Diagram for Trello helps you identify problem areas in order to achieve a predictable workflow and a healthy process. The diagram enables you to evaluate the stability of your system as, in a stable system, the average arrival rate is roughly equal to the average throughput rate. This means that the tasks arrive in the process at the same speed as they leave it.
Based on Little's Law, Average Cycle Time = Average Work In Progress / Average Throughput. Use this formula to evaluate the stability of your workflow.
The Cumulative Flow Diagram for Trello shows the exact amount of work in each state of your process. If one or more of the areas that represent WIP start to expand, this is a warning of a bottleneck in your process.
Before you jump straight to any conclusions, remember to account for changes like a shifting team size or any public holidays - these could explain any unexpected spikes in your activity.