Scrum - Calculating Sprint Velocity

Question

I need some help in answering questions

This is Sprint 1 and I have a 2 week sprint with the first week completed and the current burndown chart looks like:

Day 1 with 50 Story points

Day 2 with 57 Story points

Day 3 with 50 Story points

Day 4 with 34 Story points

Day 5 with 25 Story points

It is assumed that work is only done on working days, so 10 days in a sprint. The remaining 5 days have not been completed.

1) What is the expected velocity for this sprint?

According to a search on google, a sprint's velocity is the amount of story points in a sprint e.g. 50 story points in total in a sprint = sprint velocity is 50.

2) What do you think the velocity should be for the next sprint?

Again from a search on google, if sprint 1 has 50 as its velocity and Sprint 2 has 40 user stories in total, therefore the velocity is 40. So (50 + 40)/2 is 45 velocity?

Answer 1

Velocity is a historical measure, not a prediction. Your velocity is an average of the past few sprints. If this sprint is your very first sprint then you have no expected velocity. Velocity is a measure of what you have done in the past, not what you plan to do in the future.

It appears you've elected to do either 50 or 57 points this sprint. If you are able to complete that, your velocity will be 57. That is, your team will have proven that it can estimate and complete about 57 points in a sprint. You should then try to schedule roughly that same amount in the next sprint.

If the next sprint you are only able to complete 40 points, then your team velocity at the end of the second sprint is (57 + 40)/2, or about 48. However, that's such a wide difference between sprints, the team needs to consider why that is. For example, was a team member missing for the second print? Were there fewer days? Or, was the estimation on some of the stories wildly inaccurate?

Answer 2

You question is very hard to answer. If your stories are all equal in size, all relatively small and can all be implemented and tested independently, than one could assume that your team will be able to continue at its current pace and will possibly finish the remaining 25 point in the remaining days.

And if the team is able to finish 50 points this sprint, they're likely to be able to deliver 50 the next one as long as team composition, availability and other circumstances don't change.

But there is a lot of buts and ifs in this prediction. Remember that Velocity is a measure of what has really been done, not a prediction. And that at the start of the previous sprint, based on the outcomes of the previous sprint's Review and Retrospective you may have uncovered that you need to change the way you work, introduce new tooling, change the team composition or do some team building activities which will lower or increase the Forecasted velocity for the next sprint.

What you can tell so far is that your current velocity is 25, that your forecast for the current sprint is to reach 50 and that you'll know for certain what your velocity of Sprint 1 is, at the end of the sprint when all work is done.

You can then use that knowledge, combined with your improvement points and feedback from the Review and Retro to do a guess of what your next Forecast can be. It may be 50 again, but it could just as well be 40 or 76.