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Velocity: Escape this Pitfall

June 17, 2019
Map showing 3 routes. One direct, short, with low average velocity. Another much longer, not direct, but with much higher average velocity.

The map above illustrates a classic problem with the common use of 'velocity' as a metric.

It is also a great illustration of the assertion I made in my previous article: A Scrum Team Increases Their Velocity by Doing Less Work. The popularity of that article has surprised me as it's been syndicated by numerous e-zines and blogs. I think it struck a chord but my explanation was rather academic — the image above simplifies the argument. I'll explain.

Scenario

Your family travels each weekend to a nearby lake. You have identified at least these 3 possible routes. Which route is fastest?

That question is a trick. It's the trick which baffles many teams and managers.

  • The shortest route is 67 kilometers and will take 68 minutes given known current traffic conditions.
  • The longest route is 91 kilometers and will take 90 minutes. This route has the highest velocity!

It is obvious the shortest route is the best. It's the most direct and we'll arrive at our destination sooner. The trouble is, we'll have go a little slower.

If a manager is with us looking at the same map, if they understand the terrain the same way we do, when they can see the options before them I'm (almost) certain they'd agree to take the route with the lowest velocity.  It is the most direct route. But if that manager does not understand the terrain, they are apt to demand the route with the highest velocity. After all, they want the team to go as fast as possible!

Please use this example when:

  • You are explaining to stakeholders why TDD appears to be slower but is in fact more direct.
  • You find yourself trying to justify building quality in.
  • Your stakeholders are confused why technical debt needs to be repaid as soon as possible.

(Please share your own examples in the comments below. I'd love to hear your stories about how velocity is misused and how this article has helped you.)

Important End Note

Do make sure however that you are always focused on the most direct route. To use this example to justify any sort of gold-plating or pre-optimization is inappropriate.

***

This article is also published at scrum.works.

 

Closing

What’s your take on this? Is your experience similar to mine?

If you’re interested in learning more from me, visit my site and contact me to explore the opportunities for your organization.

Join me for a Scrum.org course: scrum.works/classes

And consider adding my recent book to your library: davidsabine.ca/phoenix


What did you think about this post?

Comments (9)


John McGinty
08:36 am June 19, 2019

It's great to highlight what Agile means by "velocity".

For me the challenge isn't just about speed (velocity is the fancy word and not accurate) but about acceleration and risk.

So when setting out on your travels (this one they know the route and have done it before unlike in the majority of dev situations) know the abilities of the vehicle, the drivers' skills, number of passengers, cargo etc to make sure we enjoy the thrills but arrive safely.


David Sabine
07:59 pm June 20, 2019

Hi John, thanks for sharing your thoughts. I agree Scrum (Empericism to be more precise) is a risk mitigation strategy.


Amit
12:36 am June 24, 2019

Very well explained


David Sabine
01:12 am June 24, 2019

Thank you, Amit. I'm glad it was clear.

I wonder if you'd be willing to elaborate... was there something in the article that you found particularly useful?


Can H.
01:02 pm June 24, 2019

Best analogy I've heard recently. Thanks


David Sabine
03:33 pm June 25, 2019

Hello Can, Thanks! I'm glad you enjoyed it. Please share with others if you found the post useful.

I wonder if anything in particular caught your interest or if you'd suggest an improvement to the article. My goal is that the analogy is meaningful and makes sense to a diverse audience.


Gilbert Kleinwechter
01:41 pm June 26, 2019

Best analogy I have seen on this topic. I so wish I had this in my tool kit a few years ago when the management could only focus on velocity and not the route it demanded.


Amit
02:44 am July 2, 2019

the example was explained with simplicity


David Sabine
05:55 pm July 2, 2019

Hi Gilbert,

I'm glad to hear you found the article interesting. Do you have other analogies in your toolkit that work? (I'm asking thinking that you, like me, are a collector of analogies/metaphors/stories. I'm always looking for new tools.)