IS214: Needs Assessment and Evaluation Introduction to Usability Assessment

What is usability? Nielsen:

Usability vs. usefulness Usability = ease of operation Utility or usefulness = serving intended purpose Both are important.

User-Centered Design “The practice of designing products so that users can perform required use, operation, service, and supportive tasks with a minimum of stress and maximum of efficiency.” “Making the design fit the user” not “Making the user fit the design.” --Woodson quoted in Rubin

Principles of User-Centered Design Set goals Target market, intended users, competition Understand users Design the total customer experience Evaluate designs Assess competitiveness Manage for users: user feedback integral to product plans, priorities, decisions --Vredenberg & others, User-Centered Design

Value of Usability Validate the business case Ensure a positive first experience for users Ensure positive on-going experience – make users’ efforts effective and efficient Provide a competitive edge Reduce customer education costs Avoid cost of redesign late in the cycle Reduce support costs Make the world a happier, more productive place

Usability Slogans Your best guess is not good enough The user is always right The user is not always right Users are not designers Designers are not users Vice Presidents are not users Details matter Help doesn’t --Nielsen, Usability Engineering

The design/assessment process My diagram Kevin McBride’s (IBM) slides

Who is on the Usability Team? --Kevin McBride, IBM UCD Project Leader Total User Experience Leader Visual Designer User Assistance Architect Technology Architect (continued…)

Who is on the Usability Team? Human-Computer Interaction Designer Marketing Specialist Service/Support Specialist Internationalization & Terminology User Research Specialist

Some Considerations in Choosing Methods Stage in the design/implementation process What you already know, need to know What difference will it make? Justification needed to make your argument Resources available Timeline

Measurement Principles Validity: measures what it purports to measure Ecological validity: represents the conditions under which a system will actually be used Reliability: gives consistent results under consistent conditions Inter-rate reliability: consistent results across testers

One Way to Classify Methods Focus: what is being investigated? User needs vs. system performance Who does the assessment? Users (or proxies) vs. experts Bases Tasks Actual (uncontrolled) or experimental (controlled) Guidelines, standards Standard or customized Setting: controlled, unnatural vs. natural

Overview of assessment methods matrix