1. Why Software Estimation is so Painful and How It Doesn’t Have To Be
Gregg Boer Principal Program Manager Microsoft Corporation Tech Ed North America 2010

2. Software development is puzzle solving

3. An estimate is a statement of probability
50%
No limit to how long it will take!

4. Fixing the faucet example How long will it take?
5 hours
10%
3 hours
1 hour
8 hours
50%
75%
90%
1 week
95%
Now

5. Estimates, targets and commitments
Now
Then
Butt on the line!

7. For each project… what’s not clear
At the start… Specific details of the nature of the software to built Details of specific requirements, Details of the solution, project plan, staffing, and other variables … are unclear (at best) Only after the sources of variability are investigate and pinned down, does the variability in the project diminish … and the variability in project estimates can also diminish

8. The degree of error created by skilled estimators at various points in the Project
Figure 1 The Cone of Uncertainty

9. “If you have another week to work on your estimate, can your refine it so it contains less uncertainty?”
Research has found… … the accuracy of the estimate depends on the level of refinement of the software’s definition. The more refined the definition, the more accurate the estimate. Reducing the variability doesn’t happen unless you reduce the variability in the project.

10. If the project is not well controlled…
… or the estimators aren’t very skilled, the estimates can fail to improve The project must be “conducted” in a way that reduces variability.

11. Reducing variability
Defined product vision (including committing to what you will not do)… Defining requirements – including what you are not going to do… Designing the user interface helps reduce the risk of variability arising from misunderstood requirements If the “project” is not defined or the product definition gets redefined, the cone gets wider. NOTE Software organizations sabotage their own projects by making commitments too early in the Cone of Uncertainty.

13. Cone of Uncertainty PMI estimates | Project Management Institute
0.67x
0.8x
1.0x
0.5x
0.25x 2x 4x
1.5x
1.25x
Project cost (effort/cost)
Product
Definition
Detailed
Technical
Requirements
Development
Design
“Order of Magnitude” (+75%, -25%)
“Budget” (+25%, -10%)
“Definitive” (+10%, -5%)
+100%
-50%

14. Puzzle solving under pressure is difficult

15. Why do people hate estimating?
You are being asked to …
Commit to hitting a specific target
For a puzzle you have never solved before
When you have the least information
Then solve the puzzle under extreme schedule pressure,
and when the date isn’t met, heads roll
That’s why.

16. Effort
Schedule
Size
Data
How long would it take…

17. What you need…
Unit
Measure

18. Some existing sizing methods
Lines of Code Function Points Pages of Requirements Screens or Web Pages

19. Story Points (Break down Features into user stories)
Priority
Product Backlog – User Stories
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20. Team work! Everyone gets a deck of cards
Planning
Poker 1
Product Backlog – User Stores 2 3 5
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Priority 13
Customize landing page 20 40
100
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21. Calibrate story points
Product Backlog – User Stories
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Completed User Stories
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Priority

22. Team members estimate the user story and Team members share their estimates
Product Backlog – User Stories
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Completed User Stories
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Priority 1 5 8

23. Team members estimate the user story and Team members share their estimates
Product Backlog – User Stories
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Completed User Stories
Add customer
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Block account 5 8 13
Priority

24. Team members estimate the user story and Team members share their estimates
Product Backlog – User Stories
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Completed User Stories
Add customer
View customer account
Log history entry
Block account 5 8 13
Priority

25. Team members estimate the user story and Team members share their estimates
Product Backlog – User Stories
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Customize landing page
Cancel delivery
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Completed User Stories
Add customer
View customer account
Log history entry
Block account 5 8 13
Priority

26. Team members estimate the user story and Team members share their estimates
Product Backlog – User Stories
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Sprint Backlog
2 weeks 5 8 13
Priority

27. Effort
Schedule
Size
Data
How long would it take…

28. Average = 9.5

29. Effort
Schedule
Size
Data
How long would it take…

30. ? We need this in 6 months! User Stories 100 story points Now Then
Data says months
Butt on the line!

31. Advantages of Story Points
Simple
Quicker feedback loops
Team A story points≠
Team B’s story points

32. What visibility do you have?
Product
Definition
Detailed
Technical
Requirements
Detailed
Development
Design

33. What value does the estimate have?
Visibility

34. Types of estimators
Optimist
Padder
Pessimist
Cynic
Pleaser

35. Those asking for the estimate
Money Bags
Intimidator
The End
is Near!
Doomsayer

36. Emotion runs wild
The End
is Near!

37. The investment matches the value

38. Expectations based on visibility
Product
Definition
Detailed
Technical
Requirements
Detailed
Development
Design

39. Re-estimate when there is more information

40. Is it an estimate or a commitment?
Now
Then
Butt on the line!

41. Estimating: Waterfall Project
What you need – the process:
Information required: Approved Business Requirements
Multiple people to estimate separately, then meet to review, revise
Apply Cone of Uncertainty applied: (-50%, +100%)
Estimate only
Re-estimate after Detailed Requirements Phase

42. Suits vs. Shirts Ask for what they want More senior Good negotiator
Determine what’s possible More junior Good with puzzles

43. Suits vs Shirts
What’s the Common goal?
Now

44. Present in ranges
Mar 1
Now
Then
January - April

45. Advice
For every estimate, demand appropriate investment Show your homework – done collaboratively Stand firm