Introduction to HCI

Samuel MoyleUniversity of Otago

New Zealand

The story so far…

• Traditionally software development uses the waterfall development model (or variations)– Investigation– Analysis– Design– Implementation– Maintenance

• So who links these together?

Who needs to know what's going on?

• Investigation – usually someone has a problem to be solved, so decisions are made about what needs to be done

• Analysis – usually an analyst(s) visits and established requirements based on the difference between what is there now and what really should be available. – What sort of skills should this person have?

Who needs to know what's going on?

• Design – Team based on area experts who put together a possible solution space.

• Domain experts have to have some knowledge about other peoples' work so they can ensure all parts will work together.

• They then plan for implementation.– Who is the key design person? Why?– Is any particular person more important than

any other?

Who needs to know what's going on?

• Implementation - takes what has been prepared by the analysts and designers, then 'follows the numbers'.

• In practice, developers need continued interaction with the client (Subject Matter Expert or SME) while they 'nut out' the hard stuff. – But who tests or sets the standard for the

development process?

What about testing with users?

• Prototypes, incremental waypoints, completed systems, all need to be assessed by users.

• Developers are rarely engaged in this process – users tend not to be interested in what goes on underneath (although more technically literate or SME's may be).

• Rather, there is a focus on the What.– But who oversees user testing or gathers

feedback at product demonstrations?

Is there a simple answer to the questions posed?

• The common person is the USER: The user needs something we should be able

to deliver. • The person/people most likely to succeed in:

– establishing user requirements (user scenarios, not just system requirements and data models),

– proposing a suitable user interface (supports user tasks by providing required system functionality), and

– can test that these user requirements have been met

will be a usability expert.

A system is more than just data and processes

• Health and safety– When things go wrong (think control systems)– Human Factors & Ergonomics

• Practical acceptability– Cost, reliability and compatibility

• Social acceptability– Problems are sometimes not due to technology

• Customers and product survival– “Software that doesn’t work well - and intuitively - will

no longer fly in today’s customer-driven market place”(Information Week, 6 Sep 1999)

Interactive Systems Design• The design of interactive systems is based on

human-computer interaction (HCI)• Practical issues include

– How should a user operate an interface?– What information should be provided at the interface to

guide interaction?– How do we integrate necessary information from

different sources, over time, and in different modalities?– How do we make that interaction as easy to use, learn,

and as pleasant as possible?– How do we check that the expected improvements have

been obtained?

So, what is HCI?

• “HCI is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of the major phenomena surrounding them.” (ACM SIGCHI, 1992)

• Matching People with Tasks and Activities, Technology, and Environment.

Inter-disciplinary Nature

• Cognitive psychology• Social and organisational psychology• Human factors and ergonomics• Linguistics• Artificial intelligence• Philosophy, sociology and anthropology• Engineering and design• Computer and Information science

Why bother with HCI?

• Is it good enough to just support function?– What work is to be done?– Fitting work to people– How do we determine and understand requirements?

• Of the worker• Of the work domain

Interaction Myths and the Usability Challenge

• The Idiot-proofing Myth• Perfect machine that is immune to imperfections of user

• The De-skilling Myth• The perfect machine so idiot-proof that organisations need fewer

and lesser qualified people to operate it

• The Usability Challenge• Technology more effective when designed to augment rather than

replace skills of users.• How best to take advantage of users’ skills in creating the most

effective and productive working environment– Paul S. Adler and Terry A. Winograd (1992). Usability: Turning technologies into tools. Oxford University Press

Interaction Paradigms

• Time sharing systems– Cards, VDUs

• WIMP– Direct manipulation, language vs. action

• Hypertext, hypermedia• Multimodal systems, VR systems• Ubiquitous computing, information appliances

– Talking to your computer or computing on your phone

Changing Technology

• Different interaction mechanisms as technology changes– E.g. command line → WIMP

• Different paradigms• Does this change the principles of what

makes a system usable?

Design Solutions• Brainstorm to get ideas how to correct the

interface. This may include SME, developers, designers…– Remember, users are not designers!

• Storyboard or Paper Prototypes– Cheap and quick to develop concepts– Workflow problems can be identified early in

development process– Prototypes are not intended for aesthetic

evaluation, but to test interaction

Aspects of Usability Dix et al (1998)

• Learnability– Ease of learning to achieve effective interaction and

maximum performance

• Flexibility– How many ways can a system and user exchange

information?

• Robustness– How to ensure successful completion of task?

• The …ilities of usability →

???All we have are questions???

• How usable are these usability principles?– Does it help us understand what is usability?– Does it help us design for usability?– Does it help us assess usability?

• Do we need something that can be measured?

Test the Design Solutions• Evaluate current systems

– What doesn't work?– Why not?

• Use the results as the basis for a new design…• Evaluate the new designs

– Do the revisions address the problems?• Take feedback and re-design… until everyone is

satisfied!• This forms the basis of a cyclic, spiral,

evolutionary, user centred, development life-cycle.

• But what can we evaluate?

Attributes of Usability

• Ease of learning• Ease of use• Ease of remembering• Few errors• Subjective satisfaction

• These attributes are measurable

What is evaluation?

• Purpose– Have functional requirements been met? – What usability problems?

• What refinements needed? Difficult to learn? Use?

– How effective is the interface?• How effectively does the system perform its job in

the intended context?

Choosing an evaluation method

• What is to be evaluated? – Design stage vs. implemented system

• Lab vs. field?– Context of actual use

• Subjective vs. Objective– Extent to which collected data is interpretive, e.g.

evaluator’s observation vs. user task times

• Qualitative vs. Quantitative– Nature of the data to be collected, e.g. description of

concepts vs. learning time

Choosing a method ...

• Immediacy of the results– How soon can the results be used?

• Intrusiveness– The extent to which the evaluator intrudes in the user’s

work and thereby affecting the outcome

• Resources needed– Pencil and paper, through to multi-angle video cameras,

quad-splitter, high quality microphones.

Summary…

• Usability Expert(s) become the binding between the development team and users

• Usability is essential if we want system development to succeed

• Usability can be measured in many ways:– Field or Lab– High-Tech or Low-Tech– Quantitative or Subjectively

Summary…

• Usability can be measured using 5 common elements– Ease of learning– Ease of use– Ease of remembering– Few errors– Subjective satisfaction

Usability is subject to the user and their work context

Questions?Questions