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Effort Estimation

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A newer version of this slide-deck is available for free (CC-BY-SA) at https://goo.gl/YnyoG4

Importance of Effort Estimation and how to get it right.

- 6 reasons why estimates tend to be wrong.
- The 7th secret reason why estimates are wrong.
- Cone of Uncertainty.
- Estimates : the usual suspects.
- How to avoid accidentally conveying confidence.

Published in: Engineering
  • An updated version of this slide-deck i used to present a session at BarCamp Bangalore Spring 2018 is now available for free at https://goo.gl/YnyoG4
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  • @Andrew Pikul Yes, glad you liked it.I've updated the license to CC-BY-SA; feel free to use the slides to discuss the principles within your team and raise awareness in general.
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  • Great post, is this yours? I'm going to use it every time a client can't believe one of my estimates.
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Effort Estimation

  1. 1. EFFORT ESTIMATION Write down the number of “squares” in the above image…
  2. 2. 5 REASONS WHY ESTIMATES TEND TO BE WRONG 1. Ambiguous/Incomplete Requirements. No documented use-cases. 2. Using Assumptions/Gut-feeling. Instead of facts. 3. Large-Scale. No breakdown structure = Omitted activities. 4. Single-Point Estimates. Average ≠ Conditional. 5. Bad work processes Bad design, code  Bugs  Rework/Firefighting.
  3. 3. THE 6TH SECRET REASON WHY ESTIMATES ARE WRONG OFF THE CUFF ESTIMATES ! Q. Can you get this done by Friday? Answer: Looks do-able. I will try. What is the right question? What is the right way to answer it?
  4. 4. CONE OF UNCERTAINTY
  5. 5. ¯_(ツ)_/¯ NOT KNOWING THE ANSWER IS OKAY
  6. 6. THE 6TH SECRET REASON WHY ESTIMATES ARE WRONG 1. Ambiguous/Incomplete Requirements. No documented use-cases. 2. Using Assumptions/Gut-feeling. Instead of facts. 3. Large-Scale. No breakdown structure = Omitted activities. 4. Single-Point Estimates. Average ≠ Conditional. 5. Bad work processes Bad design, code  Bugs  Rework/Firefighting. 5 REASONS Q. Can you get this done by Friday? Answer: Looks do-able. I will try.
  7. 7. RIGHT QUESTION? / RIGHT WAY TO ANSWER IT? 1. Ambiguous/Incomplete Requirements. No documented use-cases. 2. Using Assumptions/Gut-feeling. Instead of facts. 3. Large-Scale. No breakdown structure = Omitted activities. 4. Single-Point Estimates. Average ≠ Conditional. 5. Bad work processes Bad design, code  Bugs  Rework/Firefighting. Q. Can you get this done by Friday? Answer: Looks do-able. I will try.
  8. 8. ESTIMATES THE USUAL SUSPECTS Reference: Software Estimation Demystifying the Black Art – Steve McConnell
  9. 9. PRECISION = UNINTENDED CONFIDENCE. It is10:30 am. You are on your way to meet a friend… You: “Will see you at the mall by 11 o’clock.” Sounds like will be there sometime before 11:05 VS. You: “Will meet you at the mall at 10:58am.” Sounds like will be there sometime before 10:59 The 2nd estimate was simply based on an ETA of 28mins shown by the navigation app at 10:30.
  10. 10. INTERESTING BITS FROM AROUND THE WORLD... Calculating Functions Points - A practical example…  stackoverflow.com/q/34473698/319204 “Function Points? Valuable, but too much effort to get right.” - Mike Cohn (Scrum Alliance)  stackoverflow.com/a/153458/319204 12 tips to better estimates  stackoverflow.com/a/35571856/319204 PMBOK – 5th Edition  A Guide to the Project Management Body of Knowledge – 5e

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