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. 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
THE 6TH SECRET REASON WHY
ESTIMATES ARE WRONGQ. 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