Lifecycle models, Agile UX and the practical issues of design

A lifecycle model gives the stages, and design has to fit into them

Intuition

A software team already has a way of working. Design cannot arrive as a separate project and hand over a finished package. It has to share the team calendar.

A lifecycle (Hartson and Pyla, 2012) is a structured framework consisting of stages and the activities that characterise the full evolution of an interaction design or a complete system or product. The lecture shows the Wheel as a lifecycle template and a simple interaction design lifecycle from Preece, Rogers and Sharp (2019). Many disciplines contribute to interaction design, and each has its own lifecycle, for example the software development lifecycle (SDLC). SDLC models named are waterfall, spiral and agile. The challenge is integrating interaction design into them.

Agile and UX fit when design runs one step ahead

Agile works in short timeboxes of one to three weeks (sprint, iteration, cycle). A working product is delivered at the end of each iteration, user feedback comes early and repeatedly, and work is re-prioritised so emergent requirements can be handled. Approaches named: eXtreme Programming (XP), Scrum, Kanban and Dynamic Systems Development Method (DSDM).

AgileUX integrates interaction design with agile because it has tight iterations, champions early and regular feedback, handles emergent requirements, and strikes a balance between flexibility and structure. Three practical areas: what user research to conduct, how much and when; how to align UX design and agile working practice; and what documentation to produce, how much and when.

User research is the data collection and analysis needed to characterise users, tasks and context of use before development begins. Timeboxing does not suit long research periods, so some user research is done in iteration 0, before implementation starts. Designing a whole product upfront causes problems because priorities change, but some upfront work is needed. The answer is parallel tracks: create a product vision before development starts and do design one iteration ahead of development (some teams two).

Exam detail

Parallel tracks advantages: no design time wasted on features never built, usability testing and contextual inquiry on the same customer visit, timely feedback from developers and customers, and flexibility if a problem is found. Documentation rules: minimal, not none. It must not replace communication and collaboration. Examples are user research results, personas, detailed interface sketches and wireframes. It conveys information and is evidence of an activity ending. Ask who will read it, who will use it, the minimum needed, duplication, and how polished it must be.

Five practical issues have short answers each

Mechanism

• Who are the users? A user interacts directly with the system to achieve the task. The lecture also contrasts people who make purchasing decisions without using it and people who receive its products. Stakeholders are people affected by the system with direct or indirect influence on requirements, and identifying them helps decide who to involve as users.
• What are the users’ needs? Users cannot tell you what they need. Explore the problem space: what information is needed to complete the task, who collaborates, and why it is done that way now. Try ideas with potential users, and focus on goals plus usability and user experience goals.
• How to generate alternatives? Humans stick with what works. Sources: flair and creativity from research and synthesis, cross-fertilisation of ideas, users generating designs, product evolution, and inspiration from similar or different products and domains.
• How to choose among alternatives? Technical feasibility (external factors are visible and measurable, like a photocopier’s speed and quality; internal factors are the mechanics, like materials), evaluation with users or peers on an interactable prototype, A/B testing, and quality thresholds.
• How to integrate with other lifecycle models? Agile UX and parallel tracks, above.

A/B testing is often used for alternative web designs. It is an online method to choose between two alternatives, users are unaware they are contributing, and setting appropriate metrics and user groups is nontrivial. Usability engineering writes down formal, verifiable usability criteria and assesses the product against them. Examples: learnability as how long a novice takes to complete a series of set tasks, and memorability as how many functions a user remembers after a month without using the product.

Pitfall

The quiz slide “a user is ___” offers three options (direct interactor, purchaser, recipient of output) without showing the answer. The slide that follows defines identifying users as difficult and introduces stakeholders as the wider group. Treat the direct interactor as the user and the others as stakeholders.

Optional aside

Lecture 3 also asks you to review the group project deliverables and sketch a lifecycle model for your own team (“My Team’s Journey”: list stages, match activities to stages, add arrows for flow). That is a project task, not examinable content.

Recall

What is the parallel tracks approach and name two of its advantages.

Create a product vision before development and do design work one iteration ahead of development. Advantages include no wasted design on unbuilt features and timely feedback from developers and customers.