Agile. Agile is not a noun we can quantify but an adjective. Why on earth are most people trying to buy some ’agile’ then ? Why are people trying to sell that they are ’doing’ agile? Maybe it's time to remember the core values of software development, and among them, feedback is a central one. Let’s try to refine our ability to understand feedback and see how it can help to produce better software

1. @rhwy || #rcfbloops
FEEDBACK LOOPSTo infinity, and beyond !…
iterative thoughts by Rui Carvalho
@rhwy#rcfbloops talk@rui.fr

2. @rhwy || #rcfbloops
WHO AM I?
AN INDEPENDENT
Software Craftsman
WITH STRONG
COMMUNITY FOCUS
@rhwy
ncrafts.io

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WHY I’M HERE TO TALK ABOUT
FEEDBACK LOOPS ?

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TIME TO FOCUS
WHAT’S REALLY IMPORTANT?

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HAVE YOU HEARD ?
• TDD IS DEAD
(David Heinemeier Hansson, @dhh)
• AGILE IS A CANCER
(Erik Meijer, @headinthebox)

6. @rhwy || #rcfbloops
HAVE YOU HEARD ?
• TDD IS DEAD
(David Heinemeier Hansson, @dhh)
• AGILE IS A CANCER
(Erik Meijer, @headinthebox)
« TDD is killing your creativity »
« .. if your company is doing TDD, leave, TDD is a
waste of time … »

7. @rhwy || #rcfbloops
FIGHT TIME?

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KEEP THAT FOR LATER

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WHY THESE
SMART PEOPLE
ARE THEY
COMPLAINING?

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What
About
You?
… AND,

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ARE YOU DOING AGILE?
• are you following a strict scrum process?
• do you produce more value than before?
• is the quality of your product better?
• do you provide that value more quickly to the
final end user?
• Are you more confident?

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Don’t you want to scream sometimes?

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HOW ARE we ARRIVED AT
THIS Mess ?

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Because people that don’t understand
core values focus on processes
HOW ARE we ARRIVED AT
THIS Mess ?

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1ST / SEMANTICS MATTER

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AGILE IS AN ADJECTIVE, NOT A NOUN
adj. : I am Happy!
noun. : Can I buy some Happy?
Nonsense,
right?

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So, why are you
doing agile then? *
* maybe not you directly, mostly your
boss or a recruiter asking for that ?…

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LET’S DEVELOP WITH AGILITY!
Agile is not an input of your
system that you can buy, but
a characteristic of your team
and your way of working

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2/ LET’S SEE FROM WHERE ALL THIS CAME

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Welcome change
Deliver frequently
Agile processes promote sustainable
development
AGILE MANIFESTO PRINCIPLES

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SCRUM
|| USUAL AGILE APPLICATION
Is only a small part of what should be done !

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AGILITY IS NOT A
SILVER BULLET PROCESS
Agile is the ability to make changes now that does’t
harm our ability to make changes in the future

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BEHIND THESE principles,
THERE IS THE values!

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AMONG OTHER VALUES …
Feedback
Communication
Simplicity
Courage
Respect

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FEEDBACK !

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XP

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AGAIN, LET’S HAVE A LOOK AT SCRUM

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WE FORGOT HALF OF THE FEEDBACK!

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WE NEED ALL LOOPS TO PROVIDE QUALITY!
Project
Management
Code & Quality

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LET’S UNDERSTAND THESE feedback loops

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ITERATION FACILITATORS
Iteration Size =
1
Task Difficulty
granularity & baby steps are the key
of good incremental software

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BECAUSE IT’S ABOUT FEEDBACK,
AND BECAUSE WE’RE DOING SMALL ITERATIONS WE CALL
THAT FEEDBACK LOOPS …

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FEEDBACK LOOPS ARE real THINGS
NOT ONLY SOFTWARE DEVELOPMENT PROJECTIONS
But,

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FEEDBACK LOOPS
FEEDBACK LOOPS OCCURS WHEN THE OUTPUT OF A
SYSTEM A FEEDS THE INPUT OF A SYSTEM B THAT IN
RETURN FEEDS THE INPUT OF THE ORIGINAL SYSTEM A
A B

35. @rhwy || #rcfbloops
AND MORE IMPORTANT,
THERE IS 2 KINDS OF FEEDBACK LOOPS:
THE POSITIVE ONE
AND THE NEGATIVE ONE
A B

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ATTENTION, Common non-sens tend to define:
Positive feedback = Good
Negative feedback = Bad
&

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GOOD BAD
IT’S NOT ABOUT
&

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AMPLIFICATION REGULATION
IT’S ABOUT
&

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POSITIVE
Feedback Loops
POSITIVE IS A LOOP GAIN THAT
MEANS :
PRODUCTION OF A WILL HELP
MORE PRODUCTION OF B, THAT
IN RETURN WILL HELP MORE AND
MORE PRODUCTION OF A
AMPLIFICATION

40. @rhwy || #rcfbloops
NEGATIVE
Feedback Loops
N E G AT I V E F E E D B A C K LO O P
OCCURS WHEN YOU NEED TO
R E D U C E F L U C T U AT I O N S O R
DISTURBANCES IN YOUR SYSTEM
REGULATION

41. @rhwy || #rcfbloops
APPLYING TO YOUR WORK:
That means, that doing small iterations , is not
the only key, you also need to understand what
objectives you are your trying to reach!

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suppose that:
- you know the domain very well,
- and receive quite good stories from your business,
- your (big) team is skilled
Then:
maybe, you'll try to setup a negative feedback loop, in order
to keep your environment stable, producing value on a
regular basis
FOR EXAMPLE,
ON A REGULAR CORPORATE PROJECT

43. @rhwy || #rcfbloops
FOR EXAMPLE,
ON A REGULAR CORPORATE PROJECT
Concretely, doing things like:
- tests (not tdd),
- measuring code coverage,
- having cyclomatic metrics
Is:
a way to (try to) ensure that code quality is stable on the
long term basis

44. @rhwy || #rcfbloops
PLEASE, NOTE
THAT YOU CAN HAVE NEGATIVE FEEDBACK LOOPS AT
PROJECT LEVEL TO ENSURE STABILITY BUT ALSO POSITIVE
FEEDBACK LOOPS AT CODE LEVEL TO ENSURE CREATIVITY

45. @rhwy || #rcfbloops
most of the times, the context means:
- you don’t know the domain at all,
- and don’t have good stories because there is no business,
- your don’t know if you’re doing the right thing !…
Then:
For sure, you’ll need to setup a positive feedback loop in
order to enhance creativity, generate and test ideas
FOR EXAMPLE,
ON STARTUP (OR NEW PROJECT)
testing ideas is the objective and value you’re trying to create in that context!

46. @rhwy || #rcfbloops
Don’t apply it as « mandatory » but:
- most of the time, for complex things it will help you emerge
a good solution
- sometimes for basic things you don’t effectively need it
- for GUI things, that’s not easy too…
Alternatively:
- Creating GUI things is great when you can watch live the
changes of your code, it’s the best design value
- a good REPL is a great way to quickly test and design too!
FOR EXAMPLE,
ABOUT TDD (THE DESIGN PROCESS NOT THE TESTS)

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ANOTHER EXAMPLE
BEER PONG
For Ground, Pots
TDD will help!
For Angle, Force:
test it live !
Constraints Boundaries

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WHAT DOES
THAT MEAN
REALLY?
(TO CONCLUDE)

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KEEP THE FOCUS ON THE Why
YOU ARE DOING SOMETHING
BEFORE THE How

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SAME RULES DON’T APPLY EVERYWHERE!
THAT’S WHY YOU NEED TO :
(aka : no silver bullet process)
- UNDERSTAND THE values
- APPLY THE principles
- PRACTICE, PRACTICE, practice

51. @rhwy || #rcfbloops
BEING A GOOD
Software craftsman
ALSO MEANS BEING
MORE PRAGMATIC
AND LESS DOGMATIC

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AGILE IS ABOUT
Feedback

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AND FEEDBACK IS ABOUT
Learning

54. @rhwy || #rcfbloops
THAT
MEANS,
Learning
Agile
IS ABOUT
Learning

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CAREFULLY SETUP AND LISTENING TO YOUR
feedback loops IS THE ONLY WAY OF
Learning
&

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AND CONTINUOUS LEARNING BY
small iterations IS THE ONLY WAY TO
BUILD THE RIGHT PRODUCT
=>

57. Practice, Practice, Practice
never forget, as a Craftsman, to

58. @rhwy || #rcfbloops
Thank you!
ncrafts.io
21-22 May 2015
Paris, France
Questions ?

59. @rhwy || #rcfbloops
the great illustrative icons came from the awesome nounproject.com
Feedback Loops
v1.4
2015-04-22