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Programmer, solution architect, user group and conference organizer, conference speaker and traveling fun code evangelist. Johannes tries to apply Agile principles to large software projects, but what he's really passionate about is sharing the experience of more fun programming with other coders around the world. Johannes is a DZone MVB and is not an employee of DZone and has posted 37 posts at DZone. You can read more from them at their website. View Full User Profile

What is the Right Iteration Length?

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When picking iteration length for an agile project, there are mainly two forces that you have to balance: The rate of learning is proportional with the number of iterations, rather than the length of the project. This means that shorter iterations help you get better faster. But each iteration has some overhead with sprint reviews, retrospectives and planning. You don’t want this overhead to dominate the effort spent on the project.

For some reason, most projects I’ve seen with little experience in iterative development prefer three week iterations. Personally, I prefer two week iterations. Here is the breakdown:

  • Three week iterations: After three months, you’ve spent about 7% of your time on iteration meetings. You’ve had 4 opportunities to improve.

  • Two week iterations: After three months, you’ve spent about 10% of your time on iteration meetings. You’ve had 6 opportunities to improve.

  • One week iterations: After three months, you’ve spent about 20% of your time on iteration meetings. You’ve had 12 opportunities to improve.

Going from 93% to 90% efficiency for a 50% increase in learning seems like a good deal. Going from 90% to 80% efficiency for a 100% increase in learning, not so much.

These numbers are of course greatly simplified. You might also consider:

  • With shorter iterations, the planning time may go down. But this takes practice – it doesn’t happen automatically.

  • With very short iterations, you may not have experienced enough to learn much from the retrospective. However, if you find that you do a timeline, and most of the things people remember happened the last week, it may not be because that’s the only time something significant happened.

  • You may consider different frequencies for different ceremonies. For example, on my current project we want to have demos with our power users. But they have to travel far to visit us. So we only have a full demo every other four weeks. We plan every two weeks and have an internal review and retrospective every two weeks.

What’s the right iteration length for your project?

Published at DZone with permission of Johannes Brodwall, author and DZone MVB. (source)

(Note: Opinions expressed in this article and its replies are the opinions of their respective authors and not those of DZone, Inc.)