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INTERACTIVE SYSTEM DESIGN & EVALUATION
UCD (User Centred Design)…
INTERACTIVE SYSTEM DESIGN & EVALUATION
- UCD (User Centred Design)
INTERACTION DESIGN
OVERVIEW
- Different approaches to interaction design
- User Centred Design
- Importance of involving users
- Iterative design
- Prototyping
- Types of prototype
WHAT'S INVOLVED
- Its a process:
- Goal-directed problem solving activity informed by intended use, target domain, materials, cost, and feasibility
- Creative activity involving imagination
- Decision-making activity to balance trade-offs
4 APPROACHES
- Extreme Caricatures
- mix in real life (Saffer, D. (2010) Designing for Interaction)
- User Centred Design
- The user knows best - focus is user goals and needs
- Activity Centred Design
- Based on behaviour surrounding particular tasks
- System Design
- Structured, rigorous process, focus on context, good for complex problems
- Genius Design
- Rapid expert design - driven by designers vision
4 BASIC ACTIVITIES
- Establish requirements
- Design alternatives
- Prototyping
- Evaluating
USER CENTRED APPROACH
PROBLEMS
UNDERSTANDING USER WANTS
- You don't know what the users want and need
- Even if you're a user, your not a typical user
- There may not be a typical user
- Users don't know what the users want and need
- Know needs and situations
- Lack imagination to tell you how to turn insights into usuable requirements
- Don't know what technology can give them
- Think of new requirements after seeing prototypes
- You need to figure out what users really need
-
WHAT IT IS
ITS A PROCESS
- Process involves:
- Early focus on users and tasks: directly studying cognitive, behavioural, anthropomorphic (having human characteristics) & attitudinal characteristics
- Empirical measurement: users reactions and performance to scenarios, manuals, simulations & prototypes are observed , recorded and analysed
- Iteractive design: when problems are found in user testing, fix them and carry out more tests
- Talking to users: users know things you don't about what they want and need.
INVOLVES USERS
- Importance of involving users
- Understanding user needs
- Functionality
- Matching system to human capabilities
- Expectation management
- Realistic expectations
- No suprises, no disappointments
- Timely training
- Communication, but no hype
- Ownership
- Make users active stakeholders
- More likely to forgive or accept problems
- Can make a big difference to acceptance and success of product
DEFINITION
https://www.interaction-design.org/literature/topics/user-centered-design.
User-centered design (UCD) is an iterative design process in which designers focus on the users and their needs in each phase of the design process. In UCD, design teams involve users throughout the design process via a variety of research and design techniques, to create highly usable and accessible products for them.
USERS / STAKEHOLDERS
3 CATAGORIES OF USER
(Eason, 1987)
- Primary: frequent, hands-on
- Secondary: occasional or via someone else
- Tertiary: affected by its introduction, or will influence its purchase
- interact directly with the product
- manage direct users
- recieve output from the product
- make the purchasing decision
- use competitors products
-
DEVELOPMENT PROCESS
ITERATIVE DEVELOPMENT
WHY IT'S NEEDED
- Your 1st designs aren't your best
- You can't fully understand your requirements untill you've tested protoypes
- There will be usability glitches
- Repeating design, development, testing:
- Recognize mistakes
- Do again better
- After preparatory phase, REPEAT:
- ANALYSE
- DESIGN
- PROTOTYPE
- EVALUATE
UNTIL satisfactory, or out of time
e.g. RAD
- Rapid Application Development
- Methodology proposed by James Martin
- More general term for rapid iterative development
- User Desiign employs JOINT APPLICATION DEVELOPMENT techniques (developers collaborate with users to produce models and prototypes)
PROTOTYPING
- In all design processes
- building and evaluating models and prototypes is essential part of development process
- Form this takes depends on type of product
- Greek "proto" = first
- Prototype is an original model or pattern
- Pattern to be followed
- Test concept
- Test performance
- In engineering:
- Small scale model
- Full-scale mockups
- Real thing, but not built by mass production
-
TYPES
EXAMPLES
- a series of screen sketches
- a storyboard
- a PowerPoint slide show
- a video simulating the use of the system
- a lump of wood
- a cardboard mock-up
- a piece of software with limited functionality written in programming language
- High-fidelity: resembles final product
- Low-fidelity: just rough indication of structure & layout
- Paper prototype: Paper, cardboard,acetate, marker, pens not code - but testable by users play-acting using the system
- Storyboard: indicates layout and structure but not testable
HIGH-FIDELITY
- looks like the real thing
- Convincing appearance and behaviour
- Functionality can be fakes
- Can be in a language thats fast to code rather than fast to run (Can be faster to develop program in Smalltalk than to implement for speed in C++)
- Danger that the users think they have the real system
TYPES
- Evolutionary: the prototype eventually becomes the product
- Platform to build prototype the same as that use to deliver final product
- Throwaway: the prototype is used to get the specifications right, then discarded
- Prototype building platform usually different
DISADVANTAGES
- |Designers reluctant to throw away design ideas in an early prototype
- Putting effort into building testable prototypes too early may mean the initial design is badly thoughtout
- If the prototype is too good - management may think project nearly finished, or can be convereted to final product
PROBLEMS SHOWING USERS
- Users not realising work involved and wanting it next week
- User want response times not possible in final product
- User can be complaisant about features
- Global: entire site
- Local: selected parts of the site
- Vertical: whole operation (depth) of a few functions
- Horizontal: wide, no detail for top level individual tasks
-
- Running: Usuable, but may be limited or partly faked
- Mockup: Very imited functionality
- Evolutionary: becomes the final product
- Throw-away: serves as a pattern
PURPOSE
- Technical issues
- Workflow, task design
- Screen layouts & information display
- Difficult, controversial, critical areas
OBJECTIVES
- To help designers make decisions about
- Necessary functionality of the target system
- Organisation of functionality and presented information
- Operation sequences
- User support needs
- Representation of application objects
- Look and feel of the interface
- Early testing of attainment of usability specifications
COMPROMISES
- What you are trying to model
- What things can be unrealistic
- What you can afford to leave out
- Slow response
- Only one sequence of inputs and choices that work
- Play acted responses
- Crude graphic design
DIMENSIONS OF PROTOTYPE
FILTERING DIMENSIONS
(Lim, Stolterman & Tenenberg (2008))
- [Filtering dimention] [Example variables]
- Appearance:size, colour, shape, form, weight
- Data: data size, data type, privacy type, heirarchy
- Functionality: system functionality, user functionality
- Interactivity: behaviour(inc. ip,op,feedback, information)
- Spatial structure: arrangement of interface or information elements, relationship among interface or information elements - which can be either 2d,3d, tangible, intangible
-
IMPLEMENTATION
- So expensive (people time/ schedule time) - thats its only done once
- Design errors are built in to the first thing you can test
- If testing is postponed until implementation is complete, there are no resources and no time to do it over when a interface design mistake is covered
- Result: design errors, unless they are really bad, are left in the product
