A newer version of this slide-deck is available for free (CC-BY-SA) at https://goo.gl/YnyoG4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