Using Defensive Pessimism to Build Great Software at YML
- 2. Using Defensive Pessimism to Build Great Software at YML The Silicon Valley iOS Developers’ Meetup — June 11, 2018
- 3. 01 Motivating Defensive Pessimism 02 UX Examples 03 Developer’s Guide to Better UX Agenda
- 7. Photo by Danyu Wang on Unsplash
- 8. Photo by Václav Pluhař on Unsplash
- 9. 2016 Ferarri 488 GTB
- 11. Some Possible Characteristics of “Beautiful” Software • Anticipatory • Aesthetically-pleasing • Focused • Frictionless • Intuitive • Innovative • It Just Works • Makes the difficult easy • Omniscient
- 12. “Simple can be harder than complex. You have to work hard to get your thinking clean to make it simple. But it’s worth it in the end because once you get there, you can move mountains.”
- 13. The Happy Path • Things people would mention to others when describing an app • What our users will experience the vast majority of the time (hopefully) • Sometimes the dominant focus for designers • Just the tip of the iceberg Happy Path What do we call this?
- 14. https://twitter.com/ronjeffries/status/586902281125232640 Sad Path !Happy Path Exception Path Edge Cases We-Didn’t-Think-It- Would-Do-That Path The Path the User Ends Up Taking
- 15. It’s Reality. Our Software Must Support Reality.
- 16. The Reality of Developing Software In the Wild Photo by Nik Shuliahin on Unsplash
- 18. Yes. We Have to Worry About These Things. • Some events require error handling and recovery: • Network requests may fail • Device may run out of memory or storage capacity • Some events are failures from which we may not be able to recover programmatically: • Hardware failures • Changes to external dependencies
- 19. Robust-By-Design Software • Considers the existence of these types of scenarios from the beginning • Does not simply “bolt them on” later • Provides a fluid, although possibly degraded, experience despite their presence
- 20. Benefits of Robust-By-Design Software • More likely to: • Be of the necessary quality • Deliver a rock-solid user experience • Easier to maintain and test • The code will be better constructed (built from interconnected components) • Less likely that other developers will cause software to regress • Less likely to crash or behave in an unexpected manner in the course of operation • More secure
- 21. User Experience Benefits of Robust-by-Design Software • Things will be more fluid • Errors, when they undoubtedly occur, will be handled smoothly • App will not unexpectedly jump between screens or display unexpected states • No blank screens • No spinners ad infinitum
- 22. How do we Create Robust-by-Design Software? • The more we practice this approach: • The more scenarios will be known to us • The better we will become at thinking about new scenarios • No expectation or requirement that we think of every possible thing which can go wrong • New scenarios may be handled by existing error handling • New support will be easier to incorporate • Think about as many of the various scenarios as we can • This is a skill that software developers must hone
- 23. We Must Practice Defensive Pessimism
- 24. Defensive Pessimism • Cognitive strategy whose practitioners: • Work through all the things which could go wrong • Plan accordingly • As a result, approach situations more fully prepared • Benefit from that extra preparation
- 25. Our software (and the people using it) will benefit if we create software which, from the beginning, is more fully prepared for what can go wrong
- 26. © 2018 YML. All rights reserved. UX Examples
- 27. A Story
- 28. What does this have to do with mobile apps?
- 30. Biggest Source of Unreliability? The Network
- 31. Network calls always succeed. The Assumption:
- 32. Networks are Inherently Unreliable Success is indeterminate due to: • Throughput variability • Non-zero latency • Topologies changes
- 33. Network-dependent apps are inherently unreliable. All UX issues are mobile quality issues until proven otherwise.
- 34. UX Implications For the best UX: • Keep users informed to keep them engaged • Transparency of behavior instills trust • Cancellable actions to provide options, other than the home button
- 35. Architectural Implications • User’s actions need to be: • Encapsulated as application behavior • Executed timely on behalf of the user • Cancellable by the user • Mapped to one or more “business logic” activities • Command Design Pattern (e.g., ProcedureKit)
- 36. © 2018 YML. All rights reserved. Developer’s Guide to Better UX
- 37. Maslow’s Hierarchy of Needs Wi-Fi
- 38. Maslow as a User Data / Content Functionality Interaction Design Graphics UX
- 39. UX is a Compromise Business Goals UX
- 40. UX is not a one person job
- 41. How can developers contribute to UX?
- 42. 01 When stuff takes time, keep the user engaged.
- 45. 02 Predict
- 46. Most apps upload hereWe start uploading here
- 48. Fake it ’til you make it
- 50. Like Action Contact Server Do Nothing Regular model Update UI
- 51. Like Action Contact Server Do Nothing Update UI Revert UI Optimistic model
- 53. “This is all your app is: a collection of tiny details. Getting the details right is the difference between something that delights, and something users tolerate.” - Jeff Atwood, CodingHorror | StackOverflow
Editor's Notes
- #13: In fact, from very early on, we led innovation in mobile. Steve Jobs was so impressed he wanted to help out when we were applying the nascent touch functionality to bring Montessorrey style teaching to the hands of children across the country. And we've been on a similar first-mover edge in terms of the latest technology and design principles throughout our history ... whether that's in web, IoT, AI, VR, AR and conversational UI ... to create powerful user experiences.
- #37: How many developers in the hall, show of hands
- #38: Bottom line - A human being, as long as basic needs are not met, they will not focus on the 3 upper layers. It is important before anything else you need food, water, warmth, rest and then security.
- #39: Data/Content - Unless we have something to show, rest doesn’t matter Functionality - We need to filter the data, decide which data to show when Interaction - How to show the data, functionality can be realized in 100s of ways. Navigation Graphics - Make it look good. If we have faulty data - poor ux Bad functionality - poor UX No navigation - poor UX Ugly visuals - poor UX
- #40: UX is not a bubble. UX is in the tension field between a lot of other interests in an organization. User have needs & wants for a s/w, but that might not align with the business goals. Then we need to see what is technologically possible, which might not overlap. UX is a compromise between needs of the user, goals of the company, feasibility of tech
- #44: Although the intention behind using the spinner is fairly right, it doesn’t keep the user engaged. General rule of thumb - 0.1 sec delay - user wont notice 1 sec delay - user will notice but without losing their train of thought 10 sec delay - user will abandon the app. Load the content progressively as it arrives.
- #45: No content?
- #52: Optimism with a foundation of pessimism