We'll initially examine how and why estimation in Agile goes so wrong, so often. A new, structured and empirical method for estimating story points will then be introduced. The method involves taking into account human and environment-related factors, as well as technical ones, assigns weighted points to them and uses a numeric formula to derive a user-story's point estimate.

1. USER STORY
POINT
ESTIMATION

2. Hello!
I am Fred Heath
Developer, Problem solver, Ruby
evangelist, Agile practitioner.
You can find me at:
@FredAtBootstrap
bootstrap.me.uk

5. “There is currently no standard unit
of measurement in software
development

6. What’s this all about
○ Current estimation methods not fit for
purpose
○ A new structured, empirical way
introduced: USP estimation
USP = User Story Point

8. 4 -
easy

9. 4 -
easyNot to
me - 16

10. but, look
here……
…………..
easy, see?

11. I suppose
you’re
right,
4 then!

15. What went wrong
Environmental
factors ignored
Ben unfamiliar with
project, programming
language and
application domain.
Technical factors
ignored
Asynchronous
processing is inherently
complex, setup is not
trivial.
Human interaction
factors ignored
Jerry charismatic and
influential leader. Peer
pressure always wins.

16. Key problems with story points
○ Inconsistent
○ Subjective
○ Unreliable

17. Velocity Assumptions
○ Stable previous velocity
○ Team doesn’t change
○ Sprint duration doesn’t change
○ Initial planning session is inerrant
○ Technology / platform doesn’t change
○ Individual productivity doesn’t change

18. USER STORY POINT ESTIMATION
A consistent, reliable, structured, empirical
estimation method

19. Use Case Point
Estimation
for Object-Oriented, Use-Case
based development

20. Use Case Points
Environmental
Factors (EF)
Project familiarity,
application experience,
motivation, language
complexity, etc.
Technical Factors (TF)
Complex algorithms,
concurrency, cross-
platform support, etc.
Use Case complexity
(UUCP)
Simple, average or
complex
Use Case Points = UUCP * TCF * ECF

21. UCP References
1. Karner, G, 1993, “Metrics for Objectory”. Diploma thesis, University
of Linköping, Sweden. No. LiTHIDA-Ex-9344:21. December 1993.
2. Smith, John, 1999, “The Estimation of Effort Based on Use-Cases.
Rational Software.Cupertino, CA.TP-171. October 1999.
3. Anda, Bente, D. Dreiem, Dag Sjøberg and Magne Jørgensen, 2001,
“Estimating Software Development Effort Based on Use-Cases -
Experiences from Industry”, The Unified Modeling Language.
Modeling Languages, Concepts, and Tools, 4th International
Conference, Toronto, Canada, October 1-5, 2001, LNCS 2185
4. Roy Clem, Project Estimation with Use Case Points, http://www.
codeproject.com/KB/architecture/usecasep.aspx

22. USP - STEP 1
PRODUCTIVITY
FACTORS

23. Productivity Factors
0.5
1.5
1
1
1
-1
-1
1.5
0 1 2-1-2

24. Total Impact
= F1 weight * F1 score
+ F2 weight * F2 score
+ F3 weight * F3 score
+ F4 weight * F4 score
+ F5 weight * F5 score
+ F6 weight * F6 score
+ F7 weight * F7 score
+ F8 weight * F8 score
X

25. P FACTOR
PF = 1.4 + (-0.03*Total Impact)

26. USP - STEP 2
USER STORY
COMPLEXITY

27. COMPLEXITY FACTORS
Factor Name
A1
Distributed or Parallel
processing
A2 Concurrency
A3 High Performance
B1 Reusability & Modularity
B2
Complex internal
Processing

28. COMPLEXITY FACTORS (cont’d)
Factor Name
B3 Ease of Use
B4 Cross-Platform Support
B5
Complex Setup or
installation
B6
Extensibility &
Compliance
B7 Security

29. USER STORY COMPLEXITY
Complexity Condition USCP
Simple No complexity factors apply 5
Average 1-2 B factors, but no A factor
apply
10
Complex At least one A factor, or
more than 2 B factors, apply
15

30. USER STORY POINTS
USP = USCP * PF

31. PRODUCTIVITY FACTORS
Name Weight Score Impact
Project Familiarity 1.5 4 6
Application Experience 0.5 4 2
Proramming paradigm
experience
1 5 5
Team Cohesion 1 4 4

32. PRODUCTIVITY FACTORS
Name Weight Score Impact
User Story Robustness 1.5 5 7.5
New team-members -1 3 -3
Proramming language
complexity
-1 3 -3
Motivation 1 5 5
TOTAL IMPACT = 23.5

33. P FACTOR
PF = 1.4 + (-0.03*23.5)
= 0.695

34. User Story
Epic: “As a user, I want to backup my hard
drive.”
Story: “As a power user, I can specify files or
folders to backup based on file size, date
created and date modified.”
USCP = 10

35. USER STORY POINTS
USP = 10 * 0.695
= 6.95

36. USP ADVANTAGES
○ Objective
○ Repeatable
○ Quick to apply
○ Adaptable to change

37. “The greatest gift is the power to
estimate things at their true worth.
Francois de la Rochefoucauld

38. CREDITS
Special thanks to all the people who made and released these awesome
resources for free:
○ Simple line icons by Mirko Monti
○ E-commerce icons by Virgil Pana
○ Streamline iconset by Webalys
○ Presentation template by SlidesCarnival

39. THANKS!
Any questions?
You can find me at:
@FredAtBootstrap
fred@bootstrap.me.uk