User-Centered Design and DevelopmentCopyright Notice484-W09 QuarterChapter 6Chapter OverviewMotivationObjectivesThe Process of Interaction DesignOverviewWhat is Interaction Design?Four Basic ActivitiesThree Key CharacteristicsSome Practical IssuesWho are the Users and Stakeholders?Three Categories of UsersWho are the stakeholders?Users’ CapabilitiesUser NeedsDesign AlternativesIDEO TechBoxThe TechBoxChoosing among AlternativesTesting Prototypes to choose among AlternativesLifecycle ModelsA Simple Interaction Design ModelTraditional ‘Waterfall’ LifecycleA Lifecycle for RAD (Rapid Applications Development)Spiral Model (Barry Boehm)Spiral Lifecycle ModelThe Star Lifecycle ModelThe Star Model (Hartson and Hix, 1989)Usability Engineering Lifecycle ModelSummaryUser-Centered Design and Development Instructor: Franz J. KurfessComputer Science Dept.Cal Poly San Luis ObispoFJK 2005Copyright Notice•These slides are a revised version of the originals provided with the book “Interaction Design” by Jennifer Preece, Yvonne Rogers, and Helen Sharp, Wiley, 2002.•I added some material, made some minor modifications, and created a custom show to select a subset.–Slides added or modified by me are marked with my initials (FJK), unless I forgot it …FJK 2005484-W09 Quarter•The slides I use in class are in the Custom Show “484-W09”. It is a subset of the whole collection in this file.•Week 4 contains slides from Chapters 6 and 7 of the textbook. •The original slides are a bit of a mess, and I cleaned up various issues–outline view didn’t show body text–quite a bit of “manual” formatting instead of styles (bulleted/numbered lists)Chapter 6The Process of Interaction DesignChapter Overview•Interaction Design Activities•Key Characteristics of the Interaction Design Process•Users and User Needs•Alternative Designs•Life Cyle ModelsFJK 2005FJK 2005Motivation•it is helpful to know about common basic activities in interaction design, and key characteristics of the design process•interaction design should be driven by the needs of the users•alternative designs can provide options for users, designers, and developers•lifecycle models for interaction design have been derived from similar ones used in software engineering and HCIFJK 2005Objectives•know about the basic activities and key characteristics of the interaction design process•be aware of different types of users and shareholders, and their potential influence on the design•be familiar with some strategies to generate alternative designs•know the main differences between SE/HCI life cycle models and one for interaction designThe Process of Interaction DesignOverview •What is Interaction Design?–Four basic activities–Three key characteristics •Some practical issues–Who are the users?–What are ‘needs’?–Where do alternatives come from?–How do you choose among alternatives?•Lifecycle models from software engineering•Lifecycle models from HCIWhat is Interaction Design? •It is a process:–a goal-directed problem solving activity informed by intended use, target domain, materials, cost, and feasibility–a creative activity–a decision-making activity to balance trade-offs• It is a representation:–a plan for development–a set of alternatives and successive elaborationsFour Basic Activities •Identifying needs and establishing requirements•Developing alternative designs•Building interactive versions of the designs–prototypes•Evaluating designsThree Key CharacteristicsThree key characteristics permeate these four activities:1. Focus on users early in the design and evaluation of the artefact2. Identify, document and agree specific usability and user experience goals3. Iteration is inevitable. Designers never get it right first timeSome Practical Issues•Who are the users?•What are ‘needs’?•Where do alternatives come from?•How do you choose among alternatives?Who are the Users and Stakeholders?•Not as obvious as one may think:–those who interact directly with the product–those who manage direct users–those who receive output from the product –those who make the purchasing decision –those who use competitor’s productsThree Categories of Users•primary: frequent hands-on•secondary: occasional or via someone else•tertiary: affected by its introduction, or will influence its purchase(Eason, 1987)Who are the stakeholders?Check-out operatorsCustomersManagers and owners• Suppliers• Local shop ownersUsers’ Capabilities•Humans vary in many dimensions: – size of hands may affect the size and positioning of input buttons – motor abilities may affect the suitability of certain input and output devices – height if designing a physical kiosk – strength - a child’s toy requires little strength to operate, but greater strength to change batteries– disabilities(e.g. sight, hearing, dexterity)User Needs•Users rarely know what is possible•Users may not know their ‘needs’ –to help them achieve their goals •Existing tasks:–their context–what information do they require?–who collaborates to achieve the task?–why is the task achieved the way it is?•Envisioned tasks:–can be rooted in existing behaviour–can be described as future scenariosDesign Alternatives•Humans stick to what they know works•But considering alternatives is important to ‘break out of the box’•Designers are trained to consider alternatives, software people generally are not•How do you generate alternatives?—‘Flair and creativity’: research and synthesis —Seek inspiration: look at similar products or look at very different productsIDEO TechBox•Library, database, website - all-in-one•Contains physical gizmos for inspirationFrom: www.ideo.com/The TechBoxChoosing among Alternatives•Evaluation with users or with peers–prototypes•Technical feasibility–some alternatives are not possible/economical•Quality thresholds: –Usability goals lead to usability criteria set early on and check regularly•safety: how safe?•utility: which functions are superfluous? •effectiveness: appropriate support, task coverage, information available•efficiency: performance measurementsTesting Prototypes to choose among AlternativesLifecycle Models•Show how activities are related to each other•Lifecycle models are:—management tools—simplified versions of reality•Many lifecycle models exist, for example:—from software