Technical Debt has become a catch-all phrase for any code that needs to be re-worked. Much like Refactoring has become a catch-all phrase for any activity that involves changing code. These fundamental misunderstandings and comfortable yet mis-applied metaphors have resulted in a plethora of poor decisions. What is technical debt? What is not technical debt? Why should we care? What is the cost of misunderstanding? What do we do about it?

1. The Technical Debt Trap
Michael J Norton
@DocOnDev
LeanDog LLC*
*The views expressed are not necessarily the views of LeanDog LLC
(but they could be)

2. Rant.begin

3. What is Technical Debt?

4. What is Technical Debt?
Ward Cunningham
oopsla’92

5. What is Technical Debt?
Ward Cunningham
Shipping first time code is
like going into debt.
oopsla’92

6. What is Technical Debt?
Ward Cunningham
Shipping first time code is
like going into debt.
A little debt speeds
development so long
as it is paid back
promptly with a
rewrite.
oopsla’92

7. What is Technical Debt?
Ward Cunningham
The danger occurs
when the debt is not
repaid.
Every minute spent on not-
quite-right code counts as
interest on that debt.
oopsla’92

8. What is Technical Debt?
Ward Cunningham
The danger occurs
when the debt is not
repaid.
Every minute spent on not-
quite-right code counts as
interest on that debt.
oopsla’92

9. Technical Debt is a Good Idea

10. Technical Debt is a Good Idea
WTF?

11. Technical Debt is a Good Idea
Strategic Design Decision

12. Technical Debt is a Good Idea
Strategic Design Decision
Allow for Rapid Delivery
To Ellicit Quick Feedback
And Correct Design

13. Technical Debt is a Metaphor
Here Be Danger

14. Metaphors Rock
We reason by analogy
Can’t keep running
at this pace
Building on a weak foundation
Puts pressure on
It’s raining men our design

15. Metaphors Rock
We reason by analogy
Can’t keep running
at this pace
Building on a weak foundation
Puts pressure on
It’s raining men our design
(hallelujah)

16. Metaphorphosis
When Metaphors go wrong
Prudent

17. Metaphorphosis
When Metaphors go wrong
Return on Investment
Short-Term Fraudulent Credit Card
Inadvertent RecklessScheme
Pyramid Debt
Auto Loan
High Interest in the Third Quadrant
Home Loan Voluntary
Intentional Loan Shark Long-Term
Prudent Student Loan
Pragmatic Leverage Operational

18. Metaphorphosis

19. Metaphorphosis
When Metaphors go wrong
“cut a lot of corners”
James Shore
http://jamesshore.com/Blog/CardMeeting/Voluntary-Technical-Debt.html
“quick and dirty”
Martin Fowler
“sloppy”
http://www.martinfowler.com/bliki/TechnicalDebt.html
David Laribee “just hack it in”
http://msdn.microsoft.com/en-us/magazine/ee819135.aspx
Steve McConnell
http://blogs.construx.com/blogs/stevemcc/archive/2007/11/01/technical-debt-2.aspx

20. That’s not what I said
Ward Cunningham
[Many] have explained the debt metaphor
and confused it with the idea that
you could write code poorly with
the intention of doing a good job later.
http://www.youtube.com/watch?v=pqeJFYwnkjE&feature=player_embedded youtube.com 2009

21. That’s not what I said
Ward Cunningham
[Many] have explained the debt metaphor
and confused it with the idea that
you could write code poorly with
the intention of doing a good job later.
http://www.youtube.com/watch?v=pqeJFYwnkjE&feature=player_embedded youtube.com 2009

22. That’s not what I said
Ward Cunningham
... confused it with
the idea that you
could write code
poorly ... youtube.com 2009

23. Clean Code is Required
Ward Cunningham
The ability to pay back debt [...]
depends upon you writing code that
is clean enough to be able to refactor
as you come to understand your
problem. youtube.com 2009

24. Clean Code is Required
Ward Cunningham
The ability to pay back debt [...]
depends upon you writing code that
is clean enough to be able to
refactor as you come to
understand your problem. youtube.com 2009

25. Dirty Code is a Bad Idea
Ward Cunningham
Dirty code is to technical debt as the
pawn broker is to financial debt.
Don't think you are ever going to get
your code back.
http://twitter.com/WardCunningham/status/3742903303 twitter 2009

26. Is it Technical Debt?
Ask yourself...
Is the code clean?
Is the code tested?
Is there a learning objective?
Is there a plan for payback?
Is the business truly informed?

27. Is it Technical Debt?
If you said no to even one
Is the code clean?
Is the code tested?
Is there a learning objective?
Is there a plan for payback?
Is the business truly informed?
Then you don’t have Technical Debt

28. You have cruft
Cruft (noun)
1. An unpleasant substance
2. The result of shoddy construction
3. Redundant, old or improperly written code

29. You have a mess
Mess (noun)
1. Disorderly accumulation, heap, or jumble
2. A state of embarrassing confusion
3. An unpleasant or difficult situation

30. Chill. It’s just semantics, man.

31. Chill. It’s just semantics, man.
JUST Semantics?
Technical Debt is Good

32. Chill. It’s just semantics, man.
JUST Semantics?
Technical Debt is Good

33. Chill. It’s just semantics, man.
JUST Semantics?
Quick and Dirty is Technical Debt is Good

34. Chill. It’s just semantics, man.
JUST Semantics?
Quick and Dirty is Good

35. Chill. It’s just semantics, man.
JUST Semantics?
Quick and Dirty is Good

36. Messy Code is a Bad Decision
Every Time

37. Messy Code is a Bad Decision
Every Time
You are a professional developer
(Professionals behave ethically)

38. Messy Code is a Bad Decision
Every Time
You are a professional developer
(Professionals behave ethically)
You are going to create unintentional cruft
(You can’t help it. It’s unintentional.)

39. Messy Code is a Bad Decision
Every Time
You are a professional developer
(Professionals behave ethically)
You are going to create unintentional cruft
(You can’t help it. It’s unintentional.)
You have to clean up the existing cruft
(Intent doesn’t alter Responsibility)

40. Grammy Doesn’t Love Me!
Setting Expectations

41. The Trap
Mess begets mess

42. The Trap
Mess begets mess
Precedent for Speed over Quality
Expectation of increased velocity
Mess slows you down
Must generate more mess to keep up

43. The Trap
Mess begets mess
Precedent for Speed over Quality
Expectation of increased velocity
Mess slows you down
Must generate more mess to keep up
Ask permission to do your job correctly

44. Avoid The Trap
Incremental Fixes Fail
http://www.jacoozi.com/blog/wp-content/uploads/2007/01/refactoring_coc_big.jpg

45. Avoid The Trap
Clean Constantly

46. Avoid The Trap
Clean Constantly
Never make an intentional mess
Monitor your “Technical Debt”
Follow the Boy Scout Rule
Quality is your responsibility

47. Avoid The Trap
Clean Constantly
Never make an intentional mess
Monitor your “Technical Debt”
Follow the Boy Scout Rule
Quality is your responsibility
NEVER ask permission to do your job correctly

48. Monitoring Cruft/Debt
A few key metrics

49. Monitoring Cruft/Debt
A few key metrics
Code Coverage
Cyclomatic Complexity
Coupling

50. Monitoring Cruft/Debt
Code Coverage

51. Monitoring Cruft/Debt
Code Coverage
Code exercised by automated tests
Monitor test types separately
Don’t set a coverage target
100% Coverage is a smell

52. Monitoring Cruft/Debt
Code Coverage
Code exercised by automated tests
Monitor test types separately
Don’t set a coverage target
100% Coverage is a smell
Monitor trends, not points

53. Monitoring Cruft/Debt
Cyclomatic Complexity

54. Monitoring Cruft/Debt
Cyclomatic Complexity
Number of logical branches in code
Direct relationship with bugs
Typically high in concentrated areas
Reduce Conditionals

55. Monitoring Cruft/Debt
Cyclomatic Complexity
Number of logical branches in code
Direct relationship with bugs
Typically high in concentrated areas
Reduce Conditionals
Monitor trends, not points

56. Monitoring Cruft/Debt
Coupling

57. Monitoring Cruft/Debt
Coupling
Interconnectedness of systems
High Coupling = Difficult to Change
Afferent (Toward) and Efferent (Away)
Dependency Injection

58. Monitoring Cruft/Debt
Coupling
Interconnectedness of systems
High Coupling = Difficult to Change
Afferent (Toward) and Efferent (Away)
Dependency Injection
Monitor trends, not points

59. Lean Start-Ups
No exceptions

60. Lean Start-Ups
No exceptions
Quick Does NOT Mean Crappy
You must have a plan for payback
Be careful of the precedent you set
Quality is STILL your responsibility

61. Lean Start-Ups
No exceptions
Quick Does NOT Mean Crappy
You must have a plan for payback
Be careful of the precedent you set
Quality is STILL your responsibility
NEVER ask permission to do your job correctly

62. Rant.end

63. Thank You!
The Technical Debt Trap
Michael J Norton
@DocOnDev
LeanDog LLC*
doc@leandog.com
*The views expressed are not necessarily the views of LeanDog LLC
(but they could be)