The flow efficiency of an issue is the percentage of days when the issue was actively worked on compared to its whole lifetime.
Related metrics
The lifetime of an issue is the amount of time between its first and last activity, according to merged data from your issue tracker and your version control system.
The active days of is the number of days on which an issue had some activity, either on GitHub or your issue tracker.
Issue activity includes all events that can be tied to the issue in question, such as commits, pull requests, and reviews. Issue status changes also count as activity.
In contrast to issue cycle time, flow efficiency takes weekends into account.
Summary
Flow efficiency measures the share of active days during the lifetime of an issue.
Example
If an issue from your issue tracker was opened on May 1st and completed on June 6th, we would first calculate that it had a ‘lifetime’ of 36 days. Then, looking at how many of those days we recorded activity coming from either child issue movement or activity from GitHub, we would calculate the number of ‘active days.’
Let’s say in this scenario, there were 14 days with activity, or active days. That would then give us the ‘flow efficiency’ of 38% by taking the percentage of active days compared to the lifetime of the issue.
Why it matters
Low flow efficiency means you could have shipped sooner, and delivered value to your customers more quickly.
Low flow efficiency also indicates problems with focus and context switching, which can negatively impact developer experience.
How to use it
If you notice an issue has a flow efficiency of less than 80%, have a discussion with your team about what caused that. Was it because there were too many other work items in progress? Was the initial piece of work not well defined, which led to bottlenecks and scope creep? Depending on the answer, you can then take steps to improve in future cycles. Possibly an opportunity here to adopt a working agreement for your team to help drive higher flow efficiency.
Where to find it
You can find flow efficiency (and other flow metrics) by clicking open an issue popup anywhere in Swarmia where you see the name of an issue.