How to create a usable site?

User-Centered Development Methodology

• User-centric, not data-centric
  • Involves users in the design process
  • Usability can be quantified and measured
• Highly Iterative
  • Involves testing and revision
• Interdisciplinary and eclectic, building on a dozen different disciplines

Fields that Usability builds on

• Computer Science
  • Implementation of website or other interface
• Engineering
  • Faster, cheaper equipment
• Ergonomics
  • Design for human factors
• Graphic design
  • Visual communication
• Technical writing
  • Textual communication
• Linguistics, artificial intelligence
  • Speech recognition, natural language processing
• Cognitive psychology
  • Perception, memory, mental models
• Sociology
  • How people interact in groups
• Anthropology
  • Study of people in their work settings
• A highly eclectic field, obviously, which offers both challenges and satisfactions

The stages of user-centered development

• Analysis
  • Needs analysis
  • User and task analysis
  • Functional analysis
  • Requirements analysis
  • Setting usability specifications
• Design
• Prototyping (Implementation)
• Evaluation (Review)

Needs analysis

• Summarizes the nature and purpose of the system
  • Type of system (website, video game, spreadsheet, etc.)
  • People it will serve
  • Benefits it will provide
• For example:
  • "The Woods Bay web site will promote tourism for the Woods Bay Cottages in Bamfield, British Columbia. It will describe the accommodations, surroundings, fishing, snorkeling, hiking, and other local attractions for potential visitors. In addition, it will provide information about traveling to Bamfield, current rates, and booking a cabin."
  • "The redesigned web site for the Plains Art Council in Burkmere, South Dakota, will foster grteater participation in the arts in the local community by providing a comprehensive listing of available art programs and servicwes and by creating a vuirtual gallery for or display space for local artists.

User and task analysis

• User analysis - characterizes the people who will use the site:
  • General considerations (age, education, experience with computers)
• Task analysis - what users will do
  • User's goals - what they want to accomplish
  • Tasks or activities carried out to achieve the goals

Functional analysis

• Functionality or computer services that users will need and what will be automated
  • Close correspondence between functions and tasks
• Examples: travel site task: "find all flights to xyz, ordered by price"
  • Needs search function and sorting capability
• Music CD site: task "buy a CD"
  • Needs secure on-line transaction functionality

Requirements analysis

• Describes the formal specifications required to implement the system:
  • Data dictionaries
  • Entity-relationship diagrams
  • Object oriented modeling
• Similar to software engineering

Setting usability specifications

• Answers question "How good is your site?"
• Performance measures (such as number of tasks completed, number of errors, etc.)
• Preference measures (such as first impression, overall satisfaction)
• Classify as a performance measure or a preference measure
  • Users should be able to log in within 3 minutes, even if they forget their passwords
  • On a scale of 1 to 5 where 1 is "very dfficult" and 5 is "very easy,"ninety percent of the users should rate the login process a 4 or above.
  • Users should hit the "back" button no more than twice when lookign for merchandise items
  • Over 95 % of our current users will perefer the redesigned site to the current site.
  • Users should be able to find the "check out" page in one click, no matter where they are in the site.
  • Users judge the page download time as "fast" or "relatively fast"when viewed via a 56K dial-up connection.
  • If they have shopped online previously, users should be satisfied with the security of our site's transaction system.'

Design

• Architecture
  • Components (building blocks) of the site
  • Relationship between them
• Organization
  • Translating the architecture into pages
  • Visual organization to create clarity and consistency
  • Layout
• Appearance
  • "Look and feel"
• At this stage you can begin to sketch layout of pages-because you know your users and what they want to do

Prototyping

• Greek "proto" = first
• Prototype is an original model or pattern
  • Global: entire site
  • Local: selected parts of the site
• Types of Prototypes
  • Evolutionary: becomes the final project
  • Throw-away: serves as a pattern
  • High fidelity: resembles final product
  • Low fidelity: just rough sketch - not close to final

A low-fidelity prototype

A high-fidelity prototype

Implementation

• This is where the website or other interface is implemented, in HTML or a programming language

Evaluation

• Expert-based evaluation
  • Bring in a usability expert
• User-based evaluation
  • Test the website or other interface with users
• In this course we will emphasize user-based evaluation

User-Centered Development Cycle

• Highly iterative

Another way of looking at it