Agile Velocity | Estimating Initial Agile Velocity

Agile Velocity by Lean Agile Training

Here is a method for estimating initial Agile Velocity that may work for you.

I expect you to use it in the context of Agile Release Planning. (Anything useful should be credited to Jeff Sutherland; any issues should be credited to me.)

First we take some assumptions or identify the facts about Agile Velocity.  Imagine the following situation:

Implementers in the Team: 5

Sprint Length: 2 weeks

Ratio: 1 SP equals about 1.5 ideal person days.  (This is based on a sample from your product backlog or your reference story set. Ideally, multiple samples, as any good statistician knows.)  (Note: SP = Story Point or Story Points.)

Focus Factor: 60%.  This means that although the people are 100% allocated to the Team, as they work, they will only get about 4.8 good hours of solid work ‘in’ per 8 hour day for this effort (project).  The rest of the time other people are asking them questions, they are reviewing email, they are going to important company meetings, having lunch, taking coffee breaks, etc.  Maybe the other work is important, but it is not work on this project.  (Survey the team to get the focus factor.  Typically in the US between 60% and 70%, I find.)

Start-up cost: 40% the 1st sprint, 20% the 2nd sprint, maybe 0% the 3rd sprint.

I give 3 reasons for this Start-up cost for Agile Velocity:

  1. The team is learning Scrum
  2. The team is forming, storming, norming, and then finally performing.
  3. The team always wants to over-commit.  I find this to be the case.  Some people do not.

In any case, experience shows that taking out 40% then 20% then 0% is a good rule of thumb.  If your team is more experienced, maybe you take out less in Agile Velocity.

***

Now we start to calculate.

5 people and 10 days = 50 person days

50 X 60% FF = 30 ideal person days

30 X (1 – 40%) = 18 ideal person days remaining

18/1.5 = 12 SP for Sprint 1.

***

30 x (1 – 20%) = 24 i.p.d remaining

24/1.5 = 16 SP for Sprint 2.

***

30/1.5 = 20 SP for Sprint 3.

***

So, those are quick guesses with one specific example (your situation will be different).  You can make the calculation more sophisticated, in the sense of catering for more factors (vacation, special situations).

In any case, these are still guesses!!!  You will soon discover the Team’s real velocity from real sprints.  Almost surely, the real velocity will be notably different.  Use that soon.  The best we can say about the mathematical estimate is that it is better than nothing.

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4 thoughts on “Agile Velocity | Estimating Initial Agile Velocity

    1. Joe Little Post author

      It is based on an example that Henrik Kniberg had. It is arbitrary.
      The ratio between 1 SP and X ideal person days should be based on a reasonable sample set from YOUR product backlog. So, say you have 50 stories, I think 7 random stories would be a reasonable same set. (I did not check my STATS book….7 or so.)
      You take the average ratio in your sample. If it is random, you are assuming that the ratio (eg, 1:1.5 is possible) applies fairly to the WHOLE population.

      Help enough?
      Regards, Joe

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