By DanielPenfield - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=28553995
As you see each step has got a specific set of metrics, which we can summarize as below:
- Project completion milestones
- Total work lead time
- Total work cycle time
- Internal errors
- Workload backlog
All these metrics we use in Agile teams, but we can take a look at metrics at different perspective - mathematics.
Queue theory - is the mathematical study of queues. Software development can be modelled as a queue system.
That's why we can use Little's law, which can be defined as:
Lead Time = WIP / Throughput
There is an interesting conclusion from the Queue theory - the more work we assign the slowest delivery will be. Try to plan 80% of the team's capacity for iteration.