Why is the velocity used for estimation greater than the actual velocity to date?

[Richard Greene]

This question is in reference to Atlassian Documentation: Viewing the Version Report

The example chart shows a line indicating the velocity for the work completed to date, but uses a line with a greater slope, i.e. a higher velocity, when projecting when the remaining work will be competed.  Why is that?  

Also, why is the vertical scale of percent completion on the right not at 100% at the point representing the total amount of work defined for the version?

[Jason Lefley · Accepted solution]

See https://www.alfresco.com/blogs/developer/2015/07/29/inside-the-jira-version-report/ and https://jira.atlassian.com/browse/JSW-12137

[Nic Brough -Adaptavist-]

Because the velocity for the remaining work is the estimate of what goes into the sprint, not how you're currently performing - it's quite rare that they're the same.

The scale is not at 100% for the same reason - you might be under or over.

[Richard Greene]

Nic,

Thanks, but I'm afraid I still don't get it.  From the example chart it looks like the team completed 8 points worth of stories in about 1 year.  But the prediction assumes they will complete the remaining ~66 points at a rate of about 15 points per year.  Why would we expect their average velocity to almost double?

The page says the Predicted Release Date is "based on your average daily velocity and the amount of estimated work remaining."  Is the average daily velocity not the same as the average velocity to date, i.e.  about 8 / 365 points per day in this example?

Richard

[Nic Brough -Adaptavist-]

The velocity is based on the average rate of progress since the version began, not the team completion over an arbitrary period in the past.

[Richard Greene]

So again, if the team has completed work at the rate of 8 pts/year, ever since the version began, why would we now expect them to start completing the remaining work at a rate of 15 pts per year?

[Nic Brough -Adaptavist-]

Because that's the rate recorded since the version began.

[Richard Greene]

On the page it says "The horizontal axis starts on the version's Start Date". That axis starts in July 2014 for the example report, so that must be when the version began, no?

"Today" is in July 2015, about 1 year later, and 8 pts have been completed as of Today. So then isn't "the rate recorded since the version began" just 8 pts/year, and not 15 pts/year?