Estimates, especially for software projects, are highly inaccurate due to various challenges and laws of nature. It is difficult to provide confident estimates for tasks as simple as a person's age or as complex as the number of bugs in a project. Parkinson's Law and the Student Syndrome mean that people will naturally procrastinate and not finish work on time if given too much time. Estimates also become less accurate the more granular they are due to exponential aggregation error. Instead of relying on estimates, it is better to measure progress using techniques like story points, cycle time, and cumulative flow diagrams, and to break work down into smaller chunks with clear requirements.

1. Lies, Damn Lies…. and
Estimates
Bhavin Kamani
Independent Agile Coach

2. Are Estimates Illusio

5. It all starts as a SIMPLE problem

6. Real
ity

7. Estimation Challenges
Provide a 90% Confident Estimate
for
How old am I?
What is the size of the largest sea turtle ever
discovered?
How many bugs will you have in your next
project?
What is the total volume of all the lakes of the

8. Important Laws of Nature
Parkinson’s Law
If you give a person 5 days to deliver a task that could be
delivered in 4, the person will find something to do with that
extra day (air fills the container)
The Student Syndrome
If given too much time, people naturally procrastinate until
late in the project, at which point they rush to complete the
work, and likely won’t finish on time
Exponential Aggregation Error
The finer grained estimates you have, the more error you are
introducing into the aggregate (the more detailed – the
further from the truth you will be)

9. Man Hours

10. Story Poi

11. Cycle Tim

12. Cumulative Flow Diagr

13. Guidelines

14. #1 Don’t Estimate if you can m

15. #2 Breakup stories over granula

16. #3 Create a strong definition of re