Velocity won’t equal the difference in the size of the backlog if anything is added, removed, or
modifi ed in the backlog. For example, suppose the backlog contains 100 story points. A sprint
delivers 10 of them, but you add 10 more story points in new features to the backlog. In that
case, the velocity for the sprint was 10 but there has been no change in the backlog’s size.