Two Agile teams start working on Application A, at the same time developing exactly same functionality. Team 1 delivers with a constant velocity… While searching on the internet about AgileEVP (Agile Earned Value Management) I came across a formula from my high school physics: v=d/t, the Average Velocity formula. I really enjoyed high school math, physics, and its exams: Two trains leave Station A at the same time traveling in the same direction, Train 1 travels with a constant velocity… Here is the formula that got me started: High School Physics Average Velocity The average velocity v of an object moving through a displacement (d) during a time interval (t) is described by the formula: v=d/t where, v = Average Velocity d = displacement t = time <!--[if !supportLineBreakNewLine]--> <!--[endif]--> Read the rest on Paulo's blog at http://agiletips.blogspot.com/2009/02/average-velocity-from-high-school.html .
- Posted by: Peter Varhol
- Posted on: February 20 2009 08:30 EST
This seems a bit like calculating your speed from the west coast of france to the east coast of siberia in countries per day. Unless all of your stories are pretty uniform in terms of how long they take to implement, the estimates are going to be misleading. The key to v=d/t is that d and t are measured in uniform increments. If that is not true, the equation does not hold.
As I understand it, the length of iterations and the "value" of a story point should be consistent across a given project, so his formula is fine. I'm missing why this is a "new" insight, though. The calculation of average velocity based on prior iterations is one of the key features of every Agile methodology I've ever heard of.
Hey Dan, Thanks for the reply. I agree with you. Stories should be consistent across a given project. In fact an estimation should not try to be an accurate measurement of the amount of work (complexity + effort) of a small piece of requirement—user story in the Agile lingo. But, as long as the estimates are (relatively) consistent to each other, the average velocity formula works fine. The continuation of the blog entry (now posted in the “To be continued…” link at the end of this blog entry) has a new insight: the team acceleration formula, and a sample of its usage in the Iteration Planning Meeting. Cheers,