This document discusses techniques for estimating project parameters and outcomes. It describes expert estimation, where an expert in the domain is asked to provide estimates. Formal modeling approaches are also discussed, like COCOMO 2 and function point analysis. Good practices for creating estimates are outlined, like providing a range instead of a single value, stating assumptions, and reviewing estimates over time. Estimation techniques like affinity mapping and analogy to past projects are presented as well. The document encourages focusing on delivering value, working iteratively, and collaborating with customers.

1. Photo by gordon (TD8316) -Creative Commons Attribution-NonCommercial-ShareAlike License https://www.flickr.com/photos/22934398@N05
Created with Haiku Deck
Guesstimate
Peter Rubarth, 2014

2. Prediction is very hard, especially if it‘s about the future
Nils Bohr

3. Exercise 1 –Expert estimation
Write down your estimates for the following facts:
1.Length of German border (in km)
2.Amount of water in Bodensee lake (in l)
3.Dollars (as notes) in circulations within the USA in 2004 (in $)
4.Birth year of Alexander the Great (year)
5.World wide revenue with movie “Titanic” (in $)
6.Latitude of Shanghai (in degrees)
7.Temperature on the surface of the sun (in °C)
8.Number of bacteria in human intestines
9.Number of works of Ludwig van Beethoven
10.Expanse of Asia (in km^2)
11.Number of stars in Milky Way
12.Number newly published books in Germany 2004-2007
13.Area covered by Hamburger Hafencity including water area (in ha)
Thankyou@projectzone-http://yourprojectzone.com/2014/03/30/uebung-team-estimation-game

4. Why do we estimate?

5. ●Prepare project bid
●Plan time, resources, …
●Foster discussion
●Determine economic feasability
●Someone told us so
●…

6. What do we estimate?

7. ●Time
●Effort
●Complexity

8. How do we estimate?

9. Expert estimation
●Ask someone who should know

10. Formal model
•COCOMO 2, Function Points, IFPUG FPA, LOC, COSMIC Full Function Point (FFP) …

11. What could go wrong?

12. Insufficient data

13. Negotiation
●Now cut that in half and we have a deal

14. Estimates become targets
●But you’ve said it will take only so long!

16. Work expands so as to fill the time available for its completion.
●Parkinson‘s Law

17. This is why buffers (or the Project Managers‘ multiplier) don‘t work.

18. Cycle of Mistrust
Deliver the wrong thing, or late
Trust breaks down
Commitments of
scope and time
Focus on schedule
© Copyright Neil Killick, Iterative, 2013

19. Good Practise

20. Clarify objectives
•For which purpose?
•What are the risks and mitigation strategies?
•Awareness of the nature of estimations?

21. Provide ranges not a single value
Likely effort from … to ….
Helps to communicate that an estimate is not a guarantee

22. Use indirection, avoid direct time estimates
•Abstract units such as Story Points, Ideal Days or T-Shirt sizes help to communicate uncertainty
•Support empiric forecasting

23. Explicitly state assumptions
Provide a disclaimer:
•Which assumptions
•Use approach and data
•Risks and possible impact
At least you have told `em

24. Review and update your estimates
•Use what you have learned
•Do not hide unwelcome news
•Burnt hours are a bad progress indicator

25. The evil of Fixed Price Contracts
Knowing it will take longer does not help, because everything is fixed (unless people really idled before)
Strong incentive to cut corners and damage quality

26. Even better practise

27. •FOCUS ON VALUE
•DELIVER SMALL SLICES
•DELIVER EARLY & FREQUENTLY
•CUSTOMER COLLABORATION
© Copyright Neil Killick, Iterative, 2013

28. EMPIRICISM
•Use actual results to predict progress

29. Useful Methods

30. Group Estimation
Don‘t rely on a single opinion
Methods:
•Wideband Delphi
•Planning Poker
•Affinity Mapping

31. Analogy Method
•Compare project to previous experience
•Use checklist to compare and classify on different dimensions
•Only useful if sufficient similarity

32. Affinity Estimation
•Silently order items relative to each other
•Build clusters
•Apply appropriate scale

33. Now it‘s your turn!

34. Exercise 2 –Affinity Estimation
1.Take first item and place it in the center
2.Take turns and position subsequent item relative to existing items
3.Reorder if you disagree
4.Do not discuss!

35. Exercise 2 –Affinity estimation
Write down your estimates for the following facts:
1.Length of German border (in km)
2.Amount of water in Bodensee lake (in l)
3.Dollars (as notes) in circulations within the USA in 2004 (in $)
4.Birth year of Alexander the Great (year)
5.World wide revenue with movie “Titanic” (in $)
6.Latitude of Shanghai (in degrees)
7.Temperature on the surface of the sun (in °C)
8.Number of bacteria in human intestines
9.Number of works of Ludwig van Beethoven
10.Expanse of Asia (in km^2)
11.Number of stars in Milky Way
12.Number newly published books in Germany 2004-2007
13.Area covered by Hamburger Hafencity including water area (in ha)
Thankyou@projectzone-http://yourprojectzone.com/2014/03/30/uebung-team-estimation-game

36. Exercise 2 –Solution
Find the solution at http://yourprojectzone.com/2014/03/30/ uebung-team-estimation-game/

37. Thank you!
Twitter: #PRubarth