In an experience report on the benefits of object-orientation for OOPSLA ‘92, Ward Cunningham observed:

“Although immature code may work fine and be completely acceptable to the customer, excess quantities will make a program unmasterable, leading to extreme specialization of programmers and finally an inflexible product. 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. Objects make the cost of this transaction tolerable. The danger occurs when the debt is not repaid. Every minute spent on not-quite-right code counts as interest on that debt.”

Thus launched the twenty-year IT journey of ”Technical Debt”; and though compelling with sufficient context… “the word Technical is too broad to be useful”¹ as a guide for structural quality and the Debt metaphor too abstract for real-world development guidance.  Ward has acknowledged that many have “explained the debt metaphor and confused it”².

This post seeks to promote applying energy toward Software Flexibility instead of Technical Debt management — beginning with two starting-point metrics:

• Application Architecture measured by Cyclic Dependency
• Software Design measured by Duplicate Code³

Like any metrics, these two derive from a belief; the fundamental purpose of:

• Object-oriented use-case-agnostic Application Architecture is to structure source code into dependency groupings
• Software Design is to ”eliminate duplication”⁴ of source code (Said another way, eliminate waste⁵.)

Consider the gains realized after two decades of using a metaphor… then imagine what a decade of measurement focus could achieve for a positive impact on global application maintainability as businesses evolve in unknown ways.

And, I challenge tool vendors to include these two Software Flexibility metrics in future offerings.

_Marvin
Updated: 9/2012

References

1. Alexander von Zitzewitz – phone conversation.
2. Ward Explains Debt Metaphor – YouTube Video
3. The author defines ‘duplicate’ as:
   1. More than one consecutive identical lines of code creating an additional maintenance point
   2. More than one method of similar structure whereas a generic method could perform the function
4. Kent Beck uses this term in “TDD By Example”, although I don’t think he makes an explicit assertion relative to Software Design.
5. Richard Askew equates the elimination of duplicate source code with the Lean principle of ‘eliminating waste’ on a LinkedIn “Lean IT Enterprise” group discussion.