Lect12 - usability1

8/10/2019 Lect12 - usability1

1/23

Plan for the next 5 weeks:

> Today: The case for usability

Usability testing 1

Usability testing 2

Heuristic analysis

Cognitive walkthrough

106CR: Designing for Usability


2/23

The lack of usability of software and thepoor design of programs are the secretshame of the [software] industry. Computing professionals themselves should

take responsibility for creating a positiveuser experience. Perhaps the mostimportant conceptual move to be taken is torecognize the critical role of design, as a

counterpoint to programming, in thecreation of computer artifacts.

Mitch Kapor in Bringing Design to Software (Edited by Terry Winograd)


3/23

The Paradigm Shift

The case for Usability Constraints on implementing Usability

Usability: Why should we care?


4/23

Paradigm Shift

In the last 25 years the focus in software design has moved from:

Fitting the person to the interfaceto

Fitting the interface to the person25 years ago:

Computing was a specialist industry producing specialist tools

Required Mathematics / computing graduates.

Design debates concentrated on the development of standards andprotocols for computer languages and software development processes:ISO, IEEE, Internet RFCs


5/23

Paradigm Shift

Change in computer use:

Mainframes in 70s Expert usersDomestic PCs / mobiles / TVs now non-expert users

As computing devices become more pervasive and as more peopleuse them in their daily lives more effort is required for usabilityissues.

Proportionally more of the code in a system is devoted to the userinterface - (McIntyre et al 1990)

20% in 1980

50% in 1990

about 80 - 90 % in web design now


6/23

Paradigm Shift

Devices are now used in a much broader setof contexts:

Globalisation - broadening the device market.

Localisation - culturally specific interfaces (particularlythe web).

Personalisationthe customisability and preferencessetting that users expect from their devices.

Interoperabilitygrowing expectations that deviceswill work together.


7/23

From Enquiry to Action

Is usability a new name for an old practice?

We find concerns about the intelligibility of interfaces indisciplines as broad as:

HCIPsychologyGraphic DesignCultural Studies

However, these disciplines are concerned with theunderstanding of human action at an explanatory level.Research output from these fields often gives very few

clues as to what to do with the information


8/23

Usability

Usability is focussed on action.

Not so concerned with WHY an interface fails butWHAT is to be changed to make it work:Actionoriented research:

Field observation / testing

Negotiation with users

Prototype building

HCI Usability

Why How

Focus on theoretical explanation Focus on practical solutions

Academic Commercial


9/23

The case for Usability

1. The Economic Case

2. The Competitive Case

3. The Legal and Ethical Case


10/23

The case for Usability

The Economic Case

Companies in the global software industry are finding it increasinglydifficult to compete on functionality or price.

Functionality: With the exception of Patents (which have always

been shaky vehicles for competitive advantage in the softwareindustry) Many vendors can offer similar products.

Price: The globalisation of the industry has meant that price levelsfor similar products has started to equalise (interesting case of Linux

/ open source)

In the absence of competition at the levels of functionality and pricevendors start to compete at the level of non-functional features such asUsability, aesthetics or lifestyle appeal.


11/23

The Economic CaseMany benefits flow from a concentration on usabilityin the case of e-commerce:

Increased likelihood of customers completing a transaction onlinecustomers who can find what they're looking for easily and quickly will bemore likely to conduct a transaction

Increased customer retention and satisfaction.Ease of use alsobuilds customer loyalty and thus greater profits over time.

Reduced costs associated with design, development andmaintenance.By gathering user data early in a project, it's more likely

that designs will be right the first time, thus minimising the total projecttime and resources required.

Reduced costs associated with support, documentation, andtraining.A usable site will mean that less support, documentation and

training is required.


12/23

The Competitive Case

Unlike real-world shopping, where switching betweensuppliers is a matter of considerable effort, in e-commerce:

Competitive sites are just a few clicks away- for a customerwho is having a negative experience with a site. Customer

experience is a key differentiator for business-to-consumer(B2C) sites.

Research shows that a negative experience with an e-

commerce site means a loss of an individual customerforever.


13/23

The Legal and Ethical case

Recent regulatory and legal activitiesprovide additionalimpetus for following accessibility guidelines, particularly inbusiness-to-government (B2G) commerce.

DDADisability discrimination Act (UK)originally introducedto promote physical access to building is being revised (partlyby case law, partly by legislation) to include access toelectronic or virtual resources.

Being locked out of a bookstore because it does not havewheelchair access is equated to being locked out of a virtualbookstore because it does not provide basic facilities foraccessibility software such as screen readers.


14/23

The Legal and Ethical case

However, there is also a more fundamentalprofessional and ethical dimension than the purelylegal one:

Poor usability is simply not polite


15/23

Cost of usability

Usable.web research shows that usability testing is not anexpense

Usability has a cost-benefit ratio of anywhere from 1:10 -1:100.

E-commerce example: for every Pound spentimplementing usability techniques the site owner will realisea benefit between 10 and 100 in increased sales.


16/23

Constraints on implementing Usability

Design Inertia

Design traditions and perspectives

Legal, contractual and process constraints


17/23

Constraints on implementing Usability

Design Inertia

Standards and traditions enshrine design

approaches and objectsmaking it very difficult torevolutionise design on the basis of usability.(costs too great, staff already trained in the old

system)

Example: The QWERTY keyboard.


18/23


Different types of designer ask very differenttypes of question:

System / technical design - how hardware and software

fit together to produce a functional system.Concentration is on functionality.

System centred design questions:

1. What can be built on this platform?2. What can I create from the available tools?3. How do I as a programmer think the system should

be designed?


19/23


Different designers ask very different types of

question:

Graphic design - often used to produce a sense of style orcorporate identity. Concentration is on aesthetics / Lookand feel.

Graphic centred design questions:

1. How do I create a good looking site?

2. What can I create from the available tools?3. How do I as a graphic designer think the system

should be designed?


20/23


21/23

The Missing questions

User centred design questions:

What do users want to do with this software?How can I make this software easier to use?How do I make the software usable by the widest number

of people?

User Centred Design?

"To users, the user interface is the system."

User-centred Information design - is concerned with theoverall communication process (System design / graphic

design / interaction).


22/23

Legal, contractual and process constraints

Classic software engineering relies on FORMAL,STRUCTURED methods for the conduct of software

development.

Traditional software / information system design requires

that the development process is:

STAGED or PHASED

Each PHASE has Identifiable outcomes that are SIGNED-OFF between client and designers

The motivation for structured methods is economic.


23/23

Traditional life cycle Problems

Key point:

The idea of discrete stageseach one finished before thenext beginsentirely rules out the idea of ITERATION.

ITERATION is essential to USER-CENTRED DESIGN, which isbased on improving the product based on user testing.

More recent development methodologies recognise theneed for STAGES to overlap.

Documents

Lect12 - usability1