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The Aggregation of Marginal Gains in Software Engineering

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The Aggregation of Marginal Gains in Software Engineering

  1. 1. Improving performance through the aggregation of marginal gains 13th August 2015
  2. 2. Agenda • What does `the aggregation of marginal gains` mean? • Could this improve the performance of our software engineering team?
  3. 3. Sir Dave Brailsford Ex-Performance Director, British Cycling General Manager, Team Sky By utilising marginal gains, these teams saw considerable success..
  4. 4. British Cycling Olympic Medal Haul 2000 - 2012
  5. 5. Team Sky Tour de France British Winners 2012 2013 2015
  6. 6. –Sir Dave Brailsford “The whole principle came from the idea that if you broke down everything you could think of that goes into riding a bike, and then improved it by 1%, you will get a significant increase when you put them all together”
  7. 7. Sleep posture is important for an athlete The team replaced the mattresses + pillows in every hotel room the riders stayed in
  8. 8. We are not a professional cycling team.
  9. 9. We are a team. We have goals.
  10. 10. requirements code test cases Product Owner User
  11. 11. Release early, release often… We want the lightbulb (the Product Owner’s feature) to get round our ‘race track’ in the shortest possible time, but not at any cost. We want to: 1. Get a functioning lightbulb round the track (scope) 2. In the shortest time possible (velocity) 3. Without sacrificing the time for subsequent lightbulbs to get round the track (quality)
  12. 12. What could our marginal gains look like?
  13. 13. requirements code test cases Product Owner User
  14. 14. What goes into the ‘code’ work product?
  15. 15. We review code
  16. 16. Not all diffs are created equal
  17. 17. Work to a maximum number of characters per line: Ideally <80 Definitely <132 It’s much easier to interpret diffs during a code review
  18. 18. We debug code
  19. 19. Commit messages vary in their usefulness
  20. 20. Elliot Carver, Bond Villain “The key to a great story is not who, or what, or when, but why.” commit message
  21. 21. We run acceptance-level automation
  22. 22. We currently run entire cake + salvos before merge: - this is dead time for a developer - doesn’t expose poorly designed code to other members of the team
  23. 23. Developers should only need to run: - @smoketest - relevant scenarios
  24. 24. requirements code test cases Product Owner User
  25. 25. What goes into our other work products?
  26. 26. We define things
  27. 27. We define terminology to help us implement a feature That same terminology will be used by the next person who works on that feature
  28. 28. Treat terminology as a deliverable Instantly resolve ambiguity you find: >1 term to describe the same thing >1 thing can be described with the same term
  29. 29. We deal with surprises
  30. 30. Surprises normally slow us down It’s better to move from up-next > blocked, rather than ready-for-test > blocked
  31. 31. Developer/Tester chat before up-next -> in-progress is there any unclear terminology here? is this a candidate for a smoke test? does this rely on any 3rd party code? is there any device-specific behaviour? is there anything here that could be difficult to automate?
  32. 32. Can this improve the performance of our team?
  33. 33. Your actions provide gains to other members of the team :) You’ll experience gains because of someone else’s actions :) However, to really understand performance we need measurements
  34. 34. –Sir Dave Brailsford “We're in the right mindset, we're looking for little things, collectively, all the time that's going to make us improve.” collectively
  35. 35. ?

Editor's Notes

  • Coined ‘Aggregated Marginal Gains’ in 2012

    He sights it as the fundamental mechanism by which his racing teams were able to improve performance

    As a result of improving performance, saw considerable success
  • The olympic medal haul jumped from 4 to 14 in 4 years
  • No british rider won the tour de france in 99 years
    Team Sky have won it 3 times in 4
  • Sleeping posture is incredibly important for an athlete
    21 stages, different hotel bed every night
    Replaced mattresses, pillows and bedding for each athlete so they got the optimum nights sleep
  • I find the idea really intriguing

    Googled around find that schools have been using it a few years to help students improve their performance
  • Lightbulb will ‘halt’ during the creation of these work products
  • Saves time, crack on with next task

    Surfaces coupling in our code quicker + out in the open
  • Make it easier for the next people who come across that feature/scenario/domain to work on it

    It will likely help you to design your implementation