Agile Metrics – Time (Part 1 of 3)
Some teams choose to use card level estimated and actual time as one of the level of effort or performance markers for project progress and health. For others it’s a requirement of the work environment due to management or business constraints. If your situation resembles one of these cases then you will need to know how to use time metrics responsibly and effectively. This series of articles will establish several common practices you can use to develop your skills for evaluating and leveraging time-based metrics in an Agile environment.
It’s important to keep in mind that time estimates are just one of the level of effort or performance markers that can be used to track team and project health. There can, and probably should be other markers in the overall mix of how team and project performance is evaluated. Story points, business value, quality of information and conversation from stand-up meetings, various product backlog characteristics, cycle time, and cumulative flow are all examples of additional views into the health and progress of a project.
In addition to using multiple views, it’s important to be deeply aware of the strengths and limits presented by each of them. The limits are many while the strengths are few. Their value comes in evaluating them in concert with one another, not in isolation. One view may suggest something that can be confirmed or negated by another view into team performance. We’ll visit and review each of these and other metrics after this series of posts on time.
The examples presented in this series are never as cut and dried as presented. Just as I previously described multiple views based on different metrics, each metric can offer multiple views. My caution is that these views shouldn’t be read like an electrocardiogram, with the expectation of a rigidly repeatable pattern from which a slight deviation could signal a catastrophic event. The examples are extracted from hundreds of sprints and dozens of projects over the course of many years and are more like seismology graphs – they reveal patterns over time that are very much context dependent.
Estimated and actual time metrics allow teams to monitor sprint progress by comparing time remaining to time spent. Respectively, this will be a burn-down and a burn-up chart in reference to the direction of the data plotted on the chart. In Figure 1, the red line represents the estimated time remaining (burn-down) while the green line represents the amount of time logged against the story cards (burn-up) over the course of a two week sprint. (The gray line is a hypothetical ideal for burn-down.)
The principle value of a burn-down/burn-up chart for time is the view it gives to intra-sprint performance. I usually look at this chart just prior to a teams’ daily stand-up to get a sense if there are any questions I need to be asking about emerging trends. In this series of posts we’ll explore several of the things to look for when preparing for a stand-up. At the end of the sprint, the burn-down/burn-up chart can be a good reference to use during the retrospective when looking for ways to improve.
The sprint shown in Figure 1 is about as ideal a picture as one can expect. It shows all the points I look for that tell me, insofar as time is concerned, the sprint performance is in good health.
- There is a cross-over point roughly in the middle of the sprint.
- At the cross-over point about half of the estimated time has been burned down.
- The burn-down time is a close match to the burn-up at both the cross-over point and the end of the sprint.
- The burn-down and burn-up lines show daily movement in their respective directions.
In Part 2, we’ll look at several cases where the cross-over point shifts and explore the issues the teams under these circumstances might be struggling with.