Talk given at 2010 CSER/CASCON conference in Toronto, Ontario, Canada.

1. Managing Community Contributions:
Lessons Learned from a Case
Study on Android and Linux
Nicolas Bettenburg
Bram Adams
Ahmed E. Hassan
Queen’s University
Daniel M. German
University ofVictoria
ANNUAL REPORT 2008
!
!
!"#$%&'#()*')'(%+'*'(,(!'*!-.,(%*
!
!
#

2. 2
What is a community
contribution?

3. 2
What is a community
contribution?
A lot of things:

4. 2
What is a community
contribution?
A lot of things:
Documentation
Graphics/Art
Source Code
Testing
Error-Report
Music
Stuffed Animals
Installation Party
Bug Fix
Feedback
FeatureAdvertisement

5. 3
What is a community
contribution?
For our study:
Documentation
Graphics/Art
Source Code
Testing
Error-Report
Music
Stuffed Animals
Installation Party
Bug Fix
Feedback
FeatureAdvertisement

6. 4
Why would you want
community contributions?
Community Member
• proposes and implements features
• suggests bug fixes
• translates code/documentation
• tests new features
• provides fast feedback
• brings new users to project
• public relations/advertisement

7. 4
Why would you want
community contributions?
Community Member
• proposes and implements features
• suggests bug fixes
• translates code/documentation
• tests new features
• provides fast feedback
• brings new users to project
• public relations/advertisement
FOR FREE!

8. 5
Competitive Advantage Market Strategy
Liability
Quality
Assurance
Patents
Product
Identity
User Integration
Issues with community
contributions

9. 6
What is an effective process to enable and manage
community contributions?
Are contributors actively engaged in the
development?
Are community contributions reviewed in a timely
fashion?
What kinds of contributions can be expected – and
which parts of the software product do they target?
Research Questions:

10. 7

11. 8
Submission
Project
Repository
Feedback
Feedback
OK OK
Conception
Contributor
Review Verification Integration
Discussion
Idea
Contribution
Feedback
(1)
(2) (3) (4) (5)

12. 8
Submission
Project
Repository
Feedback
Feedback
OK OK
Conception
Contributor
Review Verification Integration
Discussion
Idea
Contribution
Feedback
(1)
(2) (3) (4) (5)

13. 8
Submission
Project
Repository
Feedback
Feedback
OK OK
Conception
Contributor
Review Verification Integration
Discussion
Idea
Contribution
Feedback
(1)
(2) (3) (4) (5)

14. 8
Submission
Project
Repository
Feedback
Feedback
OK OK
Conception
Contributor
Review Verification Integration
Discussion
Idea
Contribution
Feedback
(1)
(2) (3) (4) (5)

15. 8
Submission
Project
Repository
Feedback
Feedback
OK OK
Conception
Contributor
Review Verification Integration
Discussion
Idea
Contribution
Feedback
(1)
(2) (3) (4) (5)

16. 8
Submission
Project
Repository
Feedback
Feedback
OK OK
Conception
Contributor
Review Verification Integration
Discussion
Idea
Contribution
Feedback
(1)
(2) (3) (4) (5)

17. 9
What is an effective process to enable and manage
community contributions?
Are contributors actively engaged in the
development?
Are community contributions reviewed in a timely
fashion?
What kinds of contributions can be expected – and
which parts of the software product do they target?
Research Questions:

18. 10
Reviewer
59%
Contributor
41%
Reviewer
44%
Contributor
56%
LINUX ANDROID

19. 10
Reviewer
59%
Contributor
41%
Reviewer
44%
Contributor
56%
LINUX ANDROID
~ 2
contributions
per person
~2-4
contributions
per person

20. 10
Reviewer
59%
Contributor
41%
Reviewer
44%
Contributor
56%
LINUX ANDROID
~ 2
contributions
per person
~2-4
contributions
per person
avg. activity ~2
months
avg. activity ~2
months

21. 11
What is an effective process to enable and manage
community contributions?
Are contributors actively engaged in the
development?
Are community contributions reviewed in a timely
fashion?
What kinds of contributions can be expected – and
which parts of the software product do they target?
Research Questions:

22. 12
Time until a first response to a
contribution is received
LINUX (2009)
Date contribution was submitted
Timeuntilfirstreply(inhours)
J Ma J No

23. 13

24. 13
400%growth of community

25. 13
400%growth of community
2x submissions per contributor

26. 13
Mailing-Lists
to manage
contributions
400%growth of community
2x submissions per contributor

27. 14

28. 14
Google
actively decided
against E-Mail!

29. 14
Google
actively decided
against E-Mail!
Instead:
web-application
(Gerrit)
to manage
contributions

30. 15
“Weʼre now responding to [Android]
platform contributions faster, with
most changes currently getting looked
at within a few business days of being
uploaded, and few changes staying
inactive for more than a few weeks at
a time.
Weʼre trying to review early and
review often. [...]
I hope that the speedy process will
lead to more interactivity during the
code reviews.”
Jean-Baptiste Queru
Open-Source Management Android

31. 16
Time until a first response to a
contribution is received
ANDROID
Date contribution was submitted
Timeuntilfirstreply(inhours)
Ma A No F Ma

32. 17
LINUX (2009) ANDROID
Time until a final conclusion to
a contribution is obtained
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0
Overall time taken for review (log hours)
DensityEstimate
REJECT
ACCEPT
0.00
0.05
0.10
0.15
0 5
Overall time taken for review (log hours)
DensityEstimate
REJECT
ACCEPT

33. 18
What is an effective process to enable and manage
community contributions?
Are contributors actively engaged in the
development?
Are community contributions reviewed in a timely
fashion?
What kinds of contributions can be expected – and
which parts of the software product do they target?
Research Questions:

34. 19
(1) Pareto Distribution:
20% of subsystems received 80%
of contributions in both projects.

35. 20
(2) Major Subsystems have
high acceptance rates:
Between 50% and 91% of contributions
are accepted in both projects.

36. 21
(3) Specific Subsystems have
very low acceptance rates:
Certain subsystems in Android are very
sensitive and rather kept private.

37. 22
TO SUMMARIZE:
• Business Model based on Product Halo
• Contribution management model
• Top priority: keep users happy
• Management of contributions important
• Give fast feedback
• Let them know of acceptance right away
• Users contribute to ‘favourite’ subsystems
• For commercial OSS some subsystems ‘off
limits’

38. 23

39. 24
2 Principles:
“The worth of a company is proportional to
the number of connected users”
Metacalfe’s Law.
“As more people get involved in a community,
participation begets more participation”
Bass’ diffusion model.
Why having user communities is desirable