Communicate time ranges or scope ranges

The Iron Triangle of Project Management represents the three key constraints, scope, time, and costs, that must be carefully balanced in any project.

You should be able to communicate based on time and on scope.

• Time: If you have a fixed deadline, you can communicate which range of features we might be able to deliver.
• Scope: If you have a fixed set of features, you can communicate in which time range we might finish the stories.

In order to answer these questions you will need two things. The backlog and the velocity chart.

Example Backlog

We have a backlog with the following user stories.

Example Velocity Chart

The projects velocity chart looks like this:

Answering when a specific set of stories is finished

If we want to estimate when story 6 will be finished, we can use the following calculations:

• Remaining work for the target story: 3 + 1 + 13 + 8 + 5 + 5 = 35
• Best-case scenario for remaining sprints: remaining work (35) / best-case velocity (15) = 2.3
• Worst-case scenario for remaining sprints: remaining work (35) / worst-case velocity (8) = 4.3

We finish our work at the end of each sprint, so we round up the estimated remaining sprints.

Answer: We expect it will take between 3 and 5 sprints to finish up until story 6.

Answering what stories are finished at a specific date

If we want to estimate what we can deliver in two months, we can use the following calculations:

• Number of full sprints until the specified date: remaining time (60 day) / sprint length (14 days) = 4
• Worst-case scenario for finished story points: worst-case velocity (8) * sprints (4) = 32
• Best-case scenario for finished story points: best-case velocity (15) * sprints (4) = 60

Answer: We expect to be able to deliver up until story 5, maybe some of the stories up until story 9, and we will definitely not deliver story 10.

References

• Project Management Triangle - Wikipedia
• Forecasting - YouTube