wou intro to usability jandrzejewski

Jakub Andrzejewski | www.janmedia.com

Introduction to Usability


Plan for today’s lecture

• What is HCI and Usability?

• User Interface

• User-Centered Design

• Why is usability important?

• Usability Guidelines

• Designing and...

• ...evaluating the Design


HCI – Human Computer Interaction

A discipline concerned with– design

– evaluation

– implementation

of interactive computing systems for human use

The study of major phenomena surrounding the interactionof humans with computers


HCI – Human Computer InteractionHCI is an interdisciplinary field, combining aspects of several major fields

including

• Computer science - for ideas concerning how to design algorithms

• Psychology and related fields - for knowledge concerning the capabilities of

human memory, motor skills, and perception; how people communicate with

each other and work in groups; and social dynamics

• Artificial intelligence and related fields - for ideas concerning how to

automate more work, or make computers that behave more like intelligent

assistants

• Computer graphics - for ideas concerning how to output visual information

• Design - for example, graphic design of visual output, industrial design of

mice and keyboards, etc.


Usability

Design methodologies in HCI aim to create user interfaces that are ‘usable’…

So what is Usability then?

The definition (ISO 9241-11)The extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use.


UsabilityUsability is a quality attribute that assesses how easy user interfaces are to use.

Usability is defined by five quality components:

– Learnability: How easy is it for users to accomplish basic tasks the first time they encounter the design?

– Efficiency: Once users have learned the design, how quickly can they perform tasks?

–Memorability: When users return to the design after a period of not using it, how easily can they reestablish proficiency?

– Errors: How many errors do users make, how severe are these errors, and how easily can they recover from the errors?

– Satisfaction: How pleasant is it to use the design?


UsabilityRemember:

The technology undernearth MUST work !


User Interface

The window through which the human interacts with some application on the computer.

But it can be also…

a particular machine, device, or other complex tool (the system).


User-Centered Design

Design

Prototype Evaluate

An iterative process


User-Centered DesignFind out

• who users are

• what their goals are

• what tasks they need to perform

Task Analysis• Characterize what steps users need to take to achieve their goal

• Create scenarios of actual use

• Decide which users and tasks to support

Design based on this

Evaluate the design•Test interface (with users, usability experts)

•Do this before implementation


Why User-Centered DesignSystem will fail if it:

• does not do what the user needs• is not appropriate for the user

Why don’t we just define a “good interface”?• There is a huge variety of users and tasks• Guidelines are usually too vague

e.g. “Provide feedback”, “Be intuitive”

That’s why we need users’ involvment !


Who Builds UI’s ?

A team of specialists (ideally)

• graphic designers

• interaction / interface designers

• technical writers

• marketers

• test engineers

• software engineers


Why Usability is Important

Good design promotes• Effectiveness and efficiency

• Feelings of satisfaction, enjoyment

Bad design threatens• Safety

• Accuracy

In the world of WWW users will LEAVE the website if it:• is difficult to use

• fails to state what it offers and what users can do

• makes people feel lost

• is hard to read and doesn’t answer users’ key questions

http://www.tanzschulebuck.de/index2.htm



Volume control

Which one is the speedometer?



What is this website about?



How do you navigate? http://www.sjb.com.au/



What do I click? http://www.crumplerbags.com/



What do I click? http://laptop.org/



How do I find things? http://www.brown.edu/



Vertical menu – is it easy to read? http://www.tampax.com/home.php



I’m outta here ! http://www.neiu.edu/~flanglab/


UI Design

UI design is humbling

• Your attempt may work right, look great

• But … users may not be able to use it

• Don’t take it personally! That’s why we iterate!


UI Design Guidelines

• There are lots of them

• Based on experience and common sense

• Often don’t say HOW to implement them


10 Design Guidelines1. Visibility of system status

The system should always keep users informed about what is going on, through appropriate feedback within reasonable time.


10 Design Guidelines1. Visibility of system status - Examples

• Hourglass

• Completion bar

• "Your order has been received" page

• "Breadcrumbs"

• Rollover buttons

• Current selection


10 Design Guidelines2. Match between system and the real world

The system should speak the users' language, with words, phrasesand concepts familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order

• File-folder tabs for navigation

• Buttons which act pushed when you click on them


10 Design Guidelines3. User control and freedom

Users often choose system functions by mistake and will need a clearly marked "emergency exit" to leave the unwanted state without having to go through an extended dialogue. Support undo and redo.

• "Undo" button• Stop button on browser• "Remove from cart"• Close window• Unplug the machine


10 Design Guidelines4. Consistency and standards

Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform conventions.

• Cart icon for shopping

• underline links and make them blue


10 Design Guidelines5. Error prevention

Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action.

• "Are you sure?" message• Validation - check for @ sign in e-mail addresses• Clear labels - "Check Out NOW."• Large enough buttons


10 Design Guidelines6. Recognition rather than recall

Minimize the user's memory load by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate.

• Choose from list of options• Mouse-over tool tips• Help system always available


10 Design Guidelines7. Flexibility and efficiency of use

Accelerators -- unseen by the novice user -- may often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users. Allow users to tailor frequent actions.

• Different methods for novice and expert - mouse vs keyboard• Frequently-used actions become first choice - on Mapquest, the addresses you've looked up show up as "Recent Searches" the next time.• First menu item in ‘Messages’ is “Write new message” – your cellphone


10 Design Guidelines8. Aesthetic and minimalist design

Dialogues should not contain information which is irrelevant or rarely needed. Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility..

• Omit unnecessary words• Leave clutter off the pages, and that adorable animated gif youthink is so cool. Cute once, annoying forever.


10 Design Guidelines9. Help users recognize, diagnose, and recover from

errorsError messages should be expressed in plain language (no codes),precisely indicate the problem, and constructively suggest a solution.

• Useful error messages - "Incorrect Password. Check to see if your caps lock key is on."• On Google - "Did you mean web site?" when you typed web site


10 Design Guidelines9. Help users recognize, diagnose, and recover from

errors


10 Design Guidelines10. Help and documentation

Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such information should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large.

• Your site should be designed so well that documentation is not necessary.• If not, documentation and help should be readily available, clear, and correct.• Popup help• Clear link to customer service


Designing a UI prototype

Many methods and tools

• paper prototyping (low-fidelity)

• computer prototyping (low and high fidelity, interactive)

• PowerPoint (low-fidelity)

• Adobe Acrobat (low-fidelity)

• Visio (low-fidelity)

• Denim (low-fidelity)

• Dreamweaver (HTML) (high-fidelity)

• Visual Basic (high-fidelity)



Which one is the best?

It depends:

• for early stage design, low fidelity: paper, PowerPoint, Visio

• more refined prototypes: Adobe Acrobat, Dreamweaver

• for high-fidelity: Visual Basic



Why is it good to prototype? Why not just implement?

• Takes only a few hours• Can test multiple alternatives• Can change easily• Allows designers to work together



Example of a paper prototype


Designing a UI storyboard

Example of a PowerPoint storyboard

What is a storyboard?Low fidelity prototype - a series of screen sketches.

Used to illustrate and organize their ideas and obtain feedback.

Benefits

• Provides an overview of the system

• Demonstrates the functionality of the storyboard elements

• Demonstrates the navigation scheme

• Can check whether the presentation is accurate and complete

• Can be evaluated by users.


Evaluating UI designs

How can we ensure that what we’ve designed works?

... TEST IT !


Usability Testing

Testing the design on real end-users !

But how many users do we need?

It’s better to test frequently with fewer users !


Usability Testing

We can get:

• Qualitative data (from notes: easy to use, problematic, ...)

• Quantitative data

• Time to complete a task

• Accuracy – how many errors


Usability Test Notes - Example


Preparation for the Test

Select your participants• understand background of intended users• use a questionnaire to get the people you need

Prepare scenarios that are• typical of the product during actual use• make prototype support these (small, yet broad)

Run pilot test• check the time• check if the prototype works as intended


Conducting the Test

Three or Four testers (preferable)

• facilitator - only team member who speaksgives instructions & encourages thoughts, opinions

•computer - knows application logic & controls italways simulates the response, w/o explanation

•observer(s) - take notes & recommendationsTypical session is approximately 1.5-2hours

preparation, the test, debriefing


Conducting the Test

1. Greet

2. Get forms filled, assure confidentiality, etc.

3. Hand pre-questionnaire

4. Test5. Facilitator hands written tasks to the user (must be unambiguous and not too ‘helpful’)

6. facilitator keeps getting “output” from participantWhat are you thinking right now?”, “Think aloud”


Conducting the Test

Concluding the test...

• Fill out post-evaluation questionnaire

• Ask questions about parts you saw problems on

• Gather impressions (likes, dislikes)

• Give thanks


Analyzing Data

Sort & prioritize observations

• what was important?

• lots of problems in the same area?

Create a written report on findings (optional)

• can be short or concise

Do not wait! Refine the prototype ASAP

Test again if needed


Heuristic Analysis

Helps find usability problems in a UI design

• Small set (3-5) of evaluators examine UI

• independently check for compliance with usability

principles (“heuristics”)

• different evaluators will find different problems

• evaluators only communicate afterwards

• findings are then aggregated

Can perform on working UI or on sketches

... is cost effective


Heuristic Analysis - Steps

1. Pre-evaluation training

• give evaluators needed domain knowledge and

information on the scenarios

2. Evaluation

• individuals evaluate and then aggregate results

3. Result Analysis

• determine how severe each problem is (priority)

• suggest a solution

4. Debriefing

• discuss the outcome with design team


Heuristic Analysis - Steps

At least two passes for each evaluator• first to get feel for flow and scope of system

• second to focus on specific elements

Assistance from domain experts• If system is walk-up-and-use or evaluators are domain experts,

then no assistance needed

• Otherwise might supply evaluators with scenarios and have

domain experts standing by


Heuristic Analysis

How many evaluators?


Summary

1. Usability is important (not a key to success though)

2. UCD is a key component of the development initiative

3. Early testing is essential

4. Usability doesn’t have to be expensive… and

5. … is may save/win big money later!


Questions ?

☺


Thank You !

Jakub Andrzejewski

[email protected]

Janmedia Interactive

wou intro to usability jandrzejewski

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