Gary MarsdenSlide 1University of Cape Town Human-Computer Interaction - 1 Gary Marsden (...

Gary Marsden Slide 1University of Cape Town

Human-Computer Interaction - 1

Gary Marsden([email protected])

July 2002


Why am I here?

Course objectives– Understand why HCI is important for software

development– How HCI can be fitted in to software engineering

practice– Programming interactive systems– Effective use of user modelling and evaluation

techniques


Roadmap

Justification of HCI Interaction styles and metaphors Interface programming toolsSystem lifecyclesTask AnalysisUser ModellingDesign GuidesPrototypingEvaluation techniques


Resources

On-line– www.acm.org/sigchi/– www.hcibib.org– www.baddesigns.com

Print– Interaction Design - Preece, Rogers & Sharp– Human-Computer Interaction - Dix, Finlay,

Abowd & Beale


Goals of HCI

Develop usable products– Usability means easy to learn, effective to use

and provide an enjoyable experience

Involve users in the design processWe will discuss why this is important in a

later lecture


Key Elements

PsychologySocial SciencesComputing ScienceEngineeringErgonomics Informatics


Radios!


What else is frustrating

Paperclip


Reasons

There are many reasons why people should improve interaction between humans can computers; we shall look at four– Business– Quality of Life– Safety– Standards


Business

Within business, investment must produce some financial return

Developing interfaces can be expensive– What is the return?


Productivity Paradox

Loosely, productivity is a measure of output for a given input configuration

Computers are supposed to enhance productivity by increasing efficiency

From 1950 to 1973, US industry showed such an increase

Since 1973, this has not been the case– A period of intense use of IT and PCs

WHY?


Paradox?

Could be a spurious correlation Landauer (1995), ex IBM, investigated

– US productivity short by 1.5% (30 Billion USD)– IT investment return down by 13.3% (0f 225

billion)– This equates to 30 Billion USD– Aha!

Well, could be– “Can use statistics like a drunk man, for support

rather than illumination”


Computerisation

What is clear is that IT investment was good (for productivity) but isn’t as good now– Formerly computerisation where manual tasks

were replaced by computers• E.g. Bank accounts

– Now, computers are used to ‘augment’ (Information Technology) - not so good

• ATM’s, telephone ‘help’ systems

– People now spend so long interacting with the IT system, they do not do their jobs

• Reason for paradox?


Computerisation


Deadlines

IT projects are notorious for being late– Temptation to ‘skip’ HCI stuff

Cooper argues that it is better to ship a good product late than a bad one early– Due to early-adopter mentality (most IT people

are early adopters)

Palm Pilot was six years late!– Go, Newton, GM, Palm

Pilot


Creeping Featurism

or “Second Systems Effect”Not just bad from SE perspectiveConfusing to user having to select options

– Microsoft Word has about 105 menu options– I started using it in 1993– The only ‘new’ feature I use is the wiggly red

line


New Products

Current attitude of many companies is ‘throwing mud against the wall’– To see what sticks

Keep releasing products until something works– If version 4.0 works, what about the poor people

who bought 1.0 - 3.0?

We need to bring users in to the design process– More later


Legal issues

Besides business considerations there are legal and ethical issues to interface design

EU has workplace safety directives for– Ergonomics: making sure chairs etc. conform to human

physical form– 90/270/EEC requires that employers when designing,

selecting, commissioning or modifying software should ensure that:

• it is suitable for the task• it is easy to use, and is adaptable• it provides feedback, • it displays information in format and at a pace suitable for

the user • it conforms to the ‘principles of software ergonomics’

This is law in many EU countries


Ethics

As developers, it is our responsibility to provide software our users can use

Users are not developers– Developers like puzzles / users do not

Developers are users– Leads them to expect all users are like them

Most researchers agree developers are to blame for hard-to-use systems– But the fault lies in the development methodologies

as most developers are nice people


Safety Critical Systems

Productivity is one thing, but poor design in safety critical systems can have catastrophic results

To protect themselves, designers of bad systems blame ‘operator error’

Kegworth air disaster– 47 killed, 74 injured due to ambiguous ‘engine

fail’ light

Ralph Nader– Handbrake failures


Designer Error

Engineers build safety systems that perform to amazing levels of excellence

They then give these systems to operators who don’t know how to use them and have not be consulted in their design

Need to think more about the ‘system’– Train users of safety critical systems as drivers

are trained

We shall look at user models and training later


Discussion

Who is to blame here?

– I step out on a road crossing with a car about 200 yards away heading towards me. The car’s ABS brake system fails, the driver tries to avoid me but strikes me. The car is a hire car. The ABS system on the car was developed by a subcontractor to the car manufacturer.


Standards

Before any legal requirement can be enforced, there needs to be a requirement

Usually called a standard– Developed by researchers & industry– Tries to be ‘non-partisan’ and include

government and academics– Huge marketing potential– Standard must be adopted– If adopted, can become a purchase point

What standards are you aware of?


ISO standards

ISO standard 9241 describes in part specifying systems for usability. It gives the following definitions:– Usability: the effectiveness, efficiency and satisfaction with which

specified users achieve specified goals in particular environments.

– Effectiveness: The accuracy and completeness with which specified users can achieve specified goals in particular environments.

– Efficiency: The resources expended in relation to the accuracy and completeness of goals achieved.

This is rare, as usability standards are hard to enforce– Software standards also rare - tends to be hardware

standards


Who cares?

Having seen why HCI is important, how come things are hard to use– Dancing bear syndrome– Jigsaw puzzle guru– SE is immature– Arrogance

• stupid users or stupid software

– Cognitive dissonance


Summary

From this unit, I hope that you have learnt:– IT is not a panacea– Programmers are good, but need better

methodologies for incorporating users into design– Users should be considered a key part of safety-

critical systems– Mechanisims exist (legal, standards etc.) to

ensure that we do get good software

In this unit we have been looking only at problems– Cheer up, the rest of the course is about

solutions!

Gary MarsdenSlide 1University of Cape Town Human-Computer Interaction - 1 Gary Marsden (...

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