Complexity Theory and Why Waterfall Development Works (Sometimes)
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The document discusses complexity theory in relation to software development, contrasting complex systems with complicated ones. It argues that while some software development can be categorized as complicated and may benefit from waterfall methodologies, most software development is complex, requiring agile practices that emphasize collaboration and continuous feedback. The author emphasizes the importance of understanding the nature of software development to prevent ineffective decisions stemming from traditional metaphors.
Complexity Theory and Why Waterfall Development Works (Sometimes)
- 1. Complexity Theory and Why Waterfall Development Works (Sometimes) Larry Apke Agile Expert www.agile-doctor.com larry@agile-doctor.com
- 2. Who Am I? Over 6 years real-world experience as a scrum master, agile coach, consultant and software development manager and over 15 years of IT experience. My passion is to help people create high-quality software on a regular basis. I am a regular speaker on Agile topics, an active member of Agile user groups, founder of the San Antonio Agile Coffee. My home is in Scottsdale Arizona where I spend my weekdays as an Agile Coach at a local financial services company.
- 3. Waterfall Development Image from Winston Royce Paper titled “Managing the Development of Large Software Systems” August 1970.
- 6. Cynefin Model Pronounced Kunevin Means “Habitat” or “Place” Dave Snowden
- 7. Complex Vs. Complicated Criteria (George Rzevski) Complex Complicated Interaction A large number of diverse components (Agents) engaged in rich interaction A large number of diverse components (Agents) engaged in interaction that can be understood
- 8. Complex Vs. Complicated Criteria (George Rzevski) Complex Complicated Autonomy Agents are largely autonomous but subject to certain laws, rules or norms; there is no central control but agent behavior is not random Agents are subject to certain laws, rules or norms; there may be central control
- 9. Complex Vs. Complicated Criteria (George Rzevski) Complex Complicated Emergence Global behavior of a complex system “emerges” from the interaction of agents and is therefore unpredictable; requires feedback – can only be understood in retrospective Predictable, but requires expertise. Can be understood beforehand.
- 10. Complex Vs. Complicated Criteria (George Rzevski) Complex Complicated Equilibrium “Far from equilibrium” because frequent occurrences of disruptive events do not allow the system to return to equilibrium. There may be disruptive events but system will return to a recognizable equilibrium.
- 11. Complex Vs. Complicated Criteria (George Rzevski) Complex Complicated Linearity Nonlinearity occasionally causes an insignificant input to be amplified into an extreme event (butterfly effect). System exhibits linearity in that output events are approximately proportional to input.
- 12. Complex Vs. Complicated Criteria (George Rzevski) Complex Complicated SelfOrganzation Capable of selforganization in response to disruptive events. Centralized control is effective in response to disruptive events.
- 13. Complex Vs. Complicated Criteria (George Rzevski) Complex Complicated CoEvolution Irreversibly co-evolve with their environments. Independent parts may need experts to understand, but can be understood and function in isolation.
- 14. Complex Vs. Complicated Complex Complicated Probe, sense, respond Sense, analyze, respond Holistic Reductionist Synthesize Analyze Deming Taylor Stock Markets, New Product Development, Invention/ Innovation Manufacturing (building a house or car) manufacturing, insurance, health care providers, public schools, banks Software Development? Software Development?
- 15. Is Software Development Complex? If software development is complex, “Knowledge of experts may be of limited value, and the effectiveness of cause-and-effect analysis is likely to be marginalized, or of short duration.” - H. William Dettmer “Systems Thinking and the Cynefin Framework” I believe that some software development can be classified as complicated in which case Waterfall Methodology will work. However, I believe that most software development falls into the complex category which is where the Agile methodologies and their emphasis on continuous feedback are more effective.
- 16. Is Software Development Complex? In fact, I believe that most of the pain found in software development stems from the very fact that the people who are in positions of power do not fundamentally understand what software is. Continuing to use metaphors from complicated endeavors (like building houses and cars) confounds the situation and leads those in charge to make decisions that are diametrically opposed to getting work done. Software development, for the most part, is a complex endeavor that involves creativity, communication and collaboration and thrives with the kind of small, co-located, dedicated teams that Agile proposes.
- 17. Solving the Wrong Problem For every complex problem there is an answer that is clear, simple, and wrong. - H L Mencken It's not at all important to get it right the first time. It's vitally important to get it right the last time. - Andrew Hunt and David Thomas
- 18. Solving the Wrong Problem Gossamer Condor – Built by Paul MacReady 1977. Photo from Smithsonian Museum. Winner of the Kremer prize established in 1959. Story described in Aza Raskun's blog.
- 19. Questions???