usability principles 1

Usability Engineering - 1

Sameer Chavan

Designing for Humans

What is a User Interface?“The place at which independent systems meet and act on or communicate with each other”

Software User Interface“Narrowly defined, the software interface comprises the input and output devices and the software that services them; Broadly defined, the interface includes everything that shapes user’s experiences with computers, including documentation, training and human support”


• To the user, the interface is the system.

• People just want to get work done.

• If the user can’t find it, the function isn’t there.


• Visual limits• Motor limits• Cognitive limits

Humans have limits

• Excessive eye movement causes visual fatigue.• Color and highlighting connote meaning.• Visual coding helps users make decisions (i.e., gray out

unavailable options).• Consistent format and layout aid visual searching.• People scan. They don’t read.


Visual limits

• Attention spans fluctuate.• Users become tired.• Users may not be able to use all of their senses.• Users have different levels of manual dexterity.• There are keyboard and mouse differences between

desktop and the Web applications• The population is aging.


Perception & motor limits

• Errors increase as people get interrupted, so limit memory load.

• Break down decision-making into manageable chunks.• People are problem-solving as they work. Don’t

complicate the process.• People have an exaggerated sense of time as they work.


Cognitive limits

• Humans expect relationships.• Humans get emotional.• Humans want and expect predictability and consistency.• Humans need context.• Humans create mental models.• Humans need forgiveness.


Human expectations

• Users must understand the objects and actions used to solve a problem.

• Allow for easy problem-solving. • Reduce distractions.• Provide adequate feedback.• Reduce error situations, or if they occur, allow users to

easily resolve them.


Summary

Design Problem

What is Usability?

• Learnability

- Easy to learn

• Efficiency

-Highly productive

• Memorability

- Easy to remember

• Errors

- Low error rate

• Satisfaction

- Pleasant to use

UI Design

Owner Engineer

Architect

Building a Custom - made house

UserProgrammer

U.I.Designer

Building a Software Product

UI Design

Real World Experiences•Tasks•Processes•Tools•Results

User’s Conceptual ModelProgrammer’s Model

•Platform•Operating System•Shell•Development tools•Guidelines

U.I.Designer’s Model

•User’s Conceptual Model•Programmer’s Model•User Interface design principles and guidelines

UI Design

What if the Engine Designers make bike?

Actual Required Bike Design

Software Life Cycle

• Stage 1: Raw Iron• Stage 2: Checklist Battles• Stage 3: Productivity Wars• Stage 4: Transparency

Four Stages of Market Maturity

Stage 1: Raw Iron Stage

•Users are excited about a new product concept.

•Users are excited by the most basic capabilities.

•Users are tolerant of/oblivious to usability problems.

•Users are willing to pay for training or even special technicians to operate the product.

•Whatever alternatives are available, they are less attractive than the new product.

•“Usability” here often means that the

product is in the field and working.

•Development team is focused

primarily on solving technical and

delivery issues so the company can

get the product out the door

Stage 2: Checklist Battles

•One or more competitors have enteredthe market.

•Functionality becomes the key differentiator for customers.

•Users gravitate toward the product with the feature set that best meets their needs.

• If users are unsure about which functionality to choose, they choose “loaded” products.

• If choosing between “easy-to-use” and “has-the-feature-I-need,” users almost always pick the latter.

•“Usability” here usually means

having the right functions.

•Developers are under pressure to

add more functionality and fix bugs

Stage 3: Productivity Wars

•All vendors offer similar functionality.

•Market has become more sophisticated and end users have increased expectations for usability.

•Users are unwilling to accept a product that takes time to learn.

•Buyers/end users consider their own productivity over other factors when deciding what to buy.

Developers work to improve the ease of learning and speed of use; this is accomplished by regularly evaluating usability and sometimes by adding helper functions such as wizards

Stage 4: Transparency

• Products have become a commodity.

• Various vendors provide nearly identical products.

• Price becomes a key differentiator.

- Usability means that the product has

essentially become invisible to users.

- There is no advantage in further modifying

the product for the targeted market.

- Companies focus on lowering production

costs

Market Maturity Model

Technology Focus

User Focus

Market Maturity Over Time

Users don‘t like Unexpectations

Access

denied

O.k., and now you‘ll doexactly what I‘m telling you !

• To succeed in market, Superior Technology is not just enough, we must supply a satisfying user experience

Technology Maturity Model

Donald Norman ….”Invisible Computers”

Usability & Software Development life cycle

Understand the User & ..

Do user Task Analysis

Define User Requirements

Develop Interactions

Concept

Develop PrototypesTest Test

Software Development Test Release

Test

RequirementsCapture

Design

Development

Usability Evaluation / Usability Testing

What suits one customer might not suit the next

• ANALYSIS– User Analysis, Task Analysis

• DESIGN– Conceptual Design, Collaborative Design, Image & graphic

Design

• TESTING– Usability Testing, Heuristic Review

• TRAINING– UI Principles Training– Usability Standards– Usability Workshops

Usability services

• Identify users of the software, their characteristics and the goals they are trying to achieve –– via surveys, interviews, and focus groups– who our users are– what their needs are– current product perceptions– most important tasks

• Remember- its easy to imagine that you are the user

User Analysis

• About 72% of the US population are sensers; only 28% are intuiters• Users are not like you

• When Intuiters Design...• We’ll put it on the right mouse button.”• Sensers, who like to see interfaces that are concrete, down-to-earth, and related

to the physical world, are more likely to forget how to access the pop-up menu on the right mouse button, lacking the visual clue.

User Analysis

IntuitersSensers

• System Requirements Describe the technical limitations consider when designing

the interface:– Color palette (web vs. Desktop)– Monitor size– Screen resolution– Browser & version (for web applications)– Performance implications (speed)– Ram– Disk space– Version of integrated software

User Analysis

• Job description/title• Typical activities associated with job (general)• Hardware experience• Software experience (range)• Experience with other applications• Where user is when s/he uses our product• When user uses product (time of day, hours per week)• How frequently user uses product

Task Analysis

“To create a product that must satisfy a broad audience of users, logic will tell you to make it as broad in its functionality as possible to accommodate the most people. Logic is wrong.”

Alan Cooper, Inmates Running the Asylum, SAM, 1999

• What kind of car would you get if you put all of the features a soccer mom wants, a carpenter wants and a budding executive wants?

• Configuring software to accommodate varying needs is easier than configuring steel.

Quotes

An analogy: building design & Software Design• Conceptual Design

– Building: framework and floor plans– UI: conceptual model supporting work

tasks and guiding user through them

• Screen Layout– Building: fixtures and furniture– UI: laying out controls and data to facilitate task completion

• Visual Design– Building: lighting, sound management, interior design– UI: choosing visual components and arranging screen elements for

aesthetic appeal and enjoyment

DESIGN - Conceptual Design

• Ad-hoc consultation• review of UI elements during

implementation• review of specification and design

documents• iterations of the product earlier in the

lifecycle (ie. errors will be caught, and corrected, earlier)

DESIGN - Collaborative Design

• UI Design Guidelines

– product strategy, consistency, layout, ease of use

• UI Design Patterns

– Navigation, screen/page patterns, page layout patterns

• UI Conceptual Design

– UI principles, rationale, features, and requirements/goals for each project/release

– illustrative, detailed designs for the most important user tasks,as well as on any new/important features, or UI elements

• Images

– Splash screens, login pages, home page images, icons

– Image library available upon request

DESIGN Standards & Guidelines

There are various types of prototypes:– Low-fidelity: drawings of software, perhaps hand-drawn on paper

– Medium fidelity: electronic drawings of software, perhaps containing some graphics

– High fidelity: actual working software, often with limited functionality compared to the actual application being designed

Software Prototype

• Give a Task to complete• Actual observation of user while on work• Capturing his mouse movements • Recording his emotions and experiences• Take user feed back• Compare competitive Applications

Demo

TESTING - Usability Testing

• Expert evaluation of an existing design, prototype, build, or competing product– point out areas of strengths and weaknesses in the design

• A low-cost addition to other testing or as a quick stand-alone service• Relies on an evaluator's (or a team of evaluators') assessment based on

expertise and established usability principles

Demo

TESTING - Heuristic Review

Thanks !

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