Evolutionary Software Quality(AmA2025)

Having the right amount of quality in a software system at the right time can make the difference between the happiness and frustration of users, customers, shareholders, and others. However, software architects often struggle to implement the appropriate level of quality in their systems.

In this talk, I introduce a thinking model that guides software architects in aiming for the right level of software quality at each stage of a system’s evolution. By combining the ISO 25010 quality model with Wardley mapping, quality aspects such as usability, performance, and maintainability are systematically assessed based on their value to various stakeholders at each phase of the system's evolution. This approach helps software architects make quality-driven decisions at the right moments, while also revealing weak spots or signs of over-engineering. Architects can thereby manage suitable, appropriate quality throughout a software system's lifecycle and make improvements as needed.

Transcript

1. Evolutionary Software Quality Markus Harrer Software Evolutionist A g i l e M e e t s A r c h i t e c t u r e 2 0 2 5 , A p r i l 3 , B e r l i n May contain traces of Wardley Mapping
2. " Markus Harrer Senior Consultant / Roth, Germany Developing great software without all the drama. • Architecture Development and Review • Software Modernization and Rightsizing • Data-Driven Analysis of Software Systems Foundation & IMPROVE https://softwareanalytics.de https://feststelltaste.de/ Instructor incl. curriculum https://markusharrer.de/ 2
3. Software Quality Why is it so complicated? 3
4. µ Quality What How is all about the not the usable orders 4
5. The right amount of quality is there, at the right time. What Does Good Software Quality Mean? Actually pretty simple, isn’t it? 5
6. 6 Challenges and first solutions
7. Source: https://en.wikipedia.org/wiki/List_of_system_quality_attributes There are so many qualities 7
8. Functional Suitability Provides functionality that meets the specified and implied needs Functional Suitability Provides functionality that meets the specified and implied needs Usability Supports users in achieving their goals effectively, efficiently, and satisfactorily. Usability Supports users in achieving their goals effectively, efficiently, and satisfactorily. Performance Efficiency Delivers appropriate response times and resource usage under given conditions. Performance Efficiency Delivers appropriate response times and resource usage under given conditions. Security Protects information and systems against unauthorized access and modification. Security Protects information and systems against unauthorized access and modification. Portability Allows the system to be transferred and run in different environments. Portability Allows the system to be transferred and run in different environments. Reliability Performs consistently under specified conditions over time. Reliability Performs consistently under specified conditions over time. Compatibility Enables interaction and data exchange with other systems or components. Compatibility Enables interaction and data exchange with other systems or components. Use a common language *yes, there is a newer version of it, but I don’t like the new one For example, the ISO 25010:2011* qualities Maintainability Allows the system to be modified, improved, corrected or adapted to changes. Maintainability Allows the system to be modified, improved, corrected or adapted to changes. 8
9. Finding what‘s needed is hard Functional Suitability Performance Efficiency Compatability Usability Reliability Security Maintainability Portability User Dev Boss Know your users’ needs Challenge assumptions ? 9
10. Quality needs change over time Functional Suitability Performance Efficiency Compatability Usability Reliability Security Maintainability Portability New Quality Goals Current Software Design for constant evolution 10
11. 11 But why is it still so hard? And what can be do to make it easier?
12. Evolutionary Thinking to become more aware of changing quality priorities Part I 12
13. Code is just 0‘s and 1‘s Architecture is in-between 0 1 13
14. Commodity Product Custom Built Genesis “Everything evolves through supply and demand competition.” Evolution Software system Wardley Maps “Evolution” 0 1 Simon Wardley Software system 14
15. Evolution Axis in Detail Concept of "Evolution" and quote from Simon Wardley / Wardley Maps, CC BY-SA 4.0 license 15
16. Evolution Axis in Detail “... the consumer desire for anything which is useful or makes a difference or creates an advantage is the driver for ubiquity … “ Demand competition None Ubiquity Concept of "Evolution" and quote from Simon Wardley / Wardley Maps, CC BY-SA 4.0 license 16
17. Evolution Axis in Detail “... the desire of providers to supply an activity to consumers is the driver for feature completeness and improvement of an activity.” Demand competition Ubiquity Supply competition Certainty None Concept of "Evolution" and quote from Simon Wardley / Wardley Maps, CC BY-SA 4.0 license 17
18. Evolution Axis & Stages Demand competition Certainty Concept of "Evolution" and quote from Simon Wardley / Wardley Maps, CC BY-SA 4.0 license Genesis Custom Built Product Commodity Ubiquity None Supply competition “Everything evolves through supply and demand competition.” 18
19. Now we can get started! 19
20. Which qualities become particularly relevant during the different phases of evolution? Functional Suitability Reliability Usability Performance Efficiency Security Maintainability Compatibility Portability 20
21. Evolution and Software Quality Demand competition Supply competition Supply competition Demand competition Genesis Custom Built Product Commodity Maintainability Reliability Functional Suitability Portability Compatibility Performance Efficiency Usability Security Maintainability Reliability Functional Suitability Portability Compatibility Performance Efficiency Usability Security Quality Characteristics Certainty Ubiquity None 21 Concept of "Evolution" and quote from Simon Wardley / Wardley Maps, CC BY-SA 4.0 license
22. Evolution and Software Quality Commodity Product Custom Built Genesis Evolution Functional Suitability Reliability Usability Performance Efficiency Security Maintainability Compatibility Portability 22
23. Evolution and Software Quality Functional Suitability Reliability Usability Performance Efficiency Security Maintainability Compatibility Portability Commodity Product Custom Built Genesis Evolution 23
24. Commodity Product Custom Built Genesis Evolution Functional Suitability Reliability Usability Performance Efficiency Security Maintainability Compatibility Portability Evolution and Software Quality 24
25. Commodity Product Custom Built Genesis Evolution Functional Suitability Reliability Usability Performance Efficiency Security What’s the Point of All of This? Maintainability Compatibility Portability Create awareness for upcoming topics! Software System ! 25
26. Commodity Product Custom Built Genesis Evolution Functional Suitability Reliability Usability Performance Efficiency Security What’s the Point of All of This? Maintainability Compatibility Portability Raise awareness for the effort needed for modernization Legacy System in production) New System (in development) 26
27. Commodity Product Custom Built Genesis Evolution Functional Suitability Reliability Usability Performance Efficiency Security What’s the Point of All of This? Maintainability Compatibility Portability Question the current approach! Maintainability Compatibility Portability Software system Clean Code 3rd Party Widgets In-memory, RDBMS, NoSQL, … Cloud Native But what was the user’s need? 27
28. Convinced? Or was that just a nice story? 28
29. Value Chains for finding the right communication approach Part II 29
30. Gamer Better gaming experience New Graphics Card Shopping App REST Services Backend Database Runtime Virtual Machines Hardware Power visible invisible Value Chain Wardley Maps “Chain of Needs” component Legend needs Sometimes you also can see those details 30
31. Which qualities provide value to Stakeholders? Functional Suitability Reliability Usability Performance Efficiency Security Maintainability Compatibility Portability User Developer Boss 31
32. Needs for Quality are very subjective Typical result of prioritized quality goals Usability Functional Suitability Reliability Performance Efficiency Value Chain User Maintainability Reliability Functional Suitability Portability Developer … … Functional Suitability Usability Reliability Security … Boss visible * *Results show the averaged prioritization of quality goals from 21 case studies completed by participants in software architecture training sessions. 32
33. Developer in Unfortunate Position Usability Functional Suitability Reliability Security User ∪ Boss Maintainability Reliability Functional Suitability Portability Performance Efficiency Compatibility Portability Maintainability Compatibility Performance Efficiency Usability Security Business Technology Developer Value Chain visible invisible 33
34. Consolidated Quality Goals Security User ∪ Boss Functional Suitability Developer Performance Efficiency Business Technology ∪ & Value Chain visible Visible to business and tech people Only visible to tech people Internal Software Qualities External Software Qualities Usability Reliability Compatibility Portability Maintainability invisible 34
35. That Might Look Somehow Familiar 35 Security Functional Suitability Performance Efficiency Portability Compatibility Maintainability Usability Reliability
36. Evolutionary Software Quality Value Chain visible Functional Suitability Reliability Usability Performance Efficiency Security Maintainability Compatibility Portability Commodity Product Custom Built Genesis Evolution Visible to business and tech Only visible for tech invisible 36
37. What’s the Point of All of This? 37 Value Chain Functional Suitability Reliability Usability Performance Efficiency Security Maintainability Compatibility Portability Commodity Product Custom Built Genesis Evolution Software system Shift from directly perceivable to indirectly perceivable qualities Recognize the critical phases! visible invisible Your communication approach here won‘t work anymore there! 37
38. Summary 38
39. Commodity Product Custom Built Genesis Evolution Evolution WE DON'T WANT TO WRITE DOCUMENTATION! WE ARE SO FAST! DOCUMENTATION IS ALWAYS OUTDATED! WE NEED COMPREHENSIVE DOCUMENTATION, OTHERWISE NO ONE WILL USE OUR STUFF! Software system Photos from freepik.com, licensed under Freepik license. Right photo by gpointstudio, left photo by kues. Without Evolutionary Software Quality Maintainability, Compatibility Functional Suitability 39
40. Software system With Evolutionary Software Quality Value Chain visible Functional Suitability Reliability Usability Performance Efficiency Security Maintainability Compatibility Portability Commodity Product Custom Built Genesis Evolution Photos from freepik.com, licensed under Freepik license. Left photo by gpointstudio, right photo by kues. Great! 40
41. “All models are wrong, but some are useful.” George Box Final (obvious) Warning 41
42. Thank you! 42
43. What Do You Think? Questions, discussions, comments? 43
44. 44 Appendix Challenging the model
45. Typical situations where it works I’m developing an authentication framework. So, I don’t need to care about security? In this case, security is your functionality / business domain. 45
46. Typical situations where it works So, we don’t need to build in quality from the beginning? Could be a valid strategy. Quality has upfront and recurring costs, which can slow you down more than necessary early on. 46
47. Typical situations where it won’t Finally, a model for the ultimate truth of life! Nope. It just helps me a lot choosing the right questions at the right time. 47
48. But typical situation can also be We don’t have these challenges with invisible qualities because we’re using existing frameworks and platforms. Ohh, now we’re getting somewhere ;-) But that’s a topic for another talk ;-) 48
49. Resources 49
50. Earlier version of these contents https://www.innoq.com/en/blog/quality-value-chain-evolution/ 50
51. Wardley Mapping Quick Start https://www.youtube.com/watch?v=IJcLmoKR6v8 Ben Mosier: The Easiest Way to Do Wardley Mapping Investing in Innovation: How Situational Awareness Can Put Your Business on the Map https://www.youtube.com/watch?v=Gfq3ocmadZo 51
52. Introduction to Wardley Maps • My personal TOP 5 for getting started • https://www.feststelltaste.de/top-5-learning-wardley-maps/ • Beginner's page by Ben Mosior • https://learnwardleymapping.com/ • My favorite presentation by Simon Wardley • https://www.youtube.com/watch?v=Ty6pOVEc3bA • Book "Wardley Maps" by Simon Wardley • https://medium.com/wardleymaps • Wardley Maps Awesome List (resource collection) • https://list.wardleymaps.com 52
53. www.innoq.com Erftstr. 15-17 50672 Köln Hermannstrasse 13 20095 Hamburg Kreuzstr. 16 80331 München Ludwigstr. 180E 63067 Offenbach Ohlauer Str. 43 10999 Berlin Krischerstr. 100 40789 Monheim +49 2173 3366-0 innoQ Deutschland GmbH Thanks again! Markus Harrer Software Evolutionist #softwaremodernization #architectureassessment #training #wardleymapping #softwareanalytics Email: markus.harrer@innoq.com More info: https://www.innoq.com/en/staff/markus-harrer/ 53 Find me later at the INNOQ booth!
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