Usability

Phases of Usability

-Analysis Phase--understand target users and target tasks --Design Phase--apply knowledge of users, tasks, and HF concepts to design products, procedures, systems. --Evaluation Phase-- verify that user needs met (throughout design process) --Iterate through phases! (may need to revisit some aspects of design) The sooner Necessary changes are discovered, the cheaper they are to correct.

Usability Data

-Going beyond initial data collection: --needs assessment --in depth analysis of competitors products --development of product specifications and goals --simulations, mockups, prototypes (beta testers) --field reports --customer/user concerns problems

Design Tips

-Use user profiles ("personas") to remain focused on the needs of the target users -Use scenarios (typical system tasks) to design and test system -Use participatory techniques (integrate end-user feedback) -Design Mockups (sometimes on paper or note cards) -Use heuristics (a set or list of guidelines/standards to ensure HF "compliance")

Heuristic List

-Visibility of system status -Match between system and the real world -User control and freedom -Consistency and standards -Error prevention -Recognition rather than recall -Flexibility and efficiency of use -Aesthetic and minimalist design -Help users recognize, diagnose, and recover from errors -Help and documentation

Usability Questions

-Who are the target users? -What are the user tasks? -What is the operational environment? -Are there similar productivity/systems? -if so, what problems/concerns exist on these systems? -What are the system goals?

Major principles of user-centered design

1. Early focus on users and tasks 2. Empirical measurement of product usage 3. Iterative design process

What is usability?

A component of system acceptance

What is Usability?

An attribute of a product or system that suggests: -Ease of use -Comfortable use -Effective/efficient use Usable systems: -work as expected for the purpose for which it was designed. -Go beyond simple "utility"- suggesting satisfying or even pleasurable use. -Utility and usefulness are necessary, but not sufficient, conditions for usability. -Usability is more than simply an "ability" to "use" something. Usability implies optimization: --Minimization of effort, stress. --Maximization of efficiency, comfort, productivity, pleasure, etc.

We just need "better" users

If our product users were not such demanding, lazy, incompetent morons, our products would be quite usable -- have these people even seen a computer? -What can be done about poor users? --we could wait for them to all die off --we could wait for them to evolve into super users --we could educate them on the nuances of our current system --or we could actually design useable systems targeted to our user population

Usability Goals

Usefulness--does the system achieve goals? Effectiveness-- ease of use (can be quantified as speed, error rate, percent of users who "get it") Learnability--competence level after a prescribed amount of time (also, time to "relearn"--"is it like riding a bike") -Errors--should be identifiable and correctable -Satisfaction--"likeability"--feelings, opinions, "coolness"

Initial Data

Where does one begin? -case studies, customer/user feedback -surveys -focus groups -task analysis -user diaries -conceptual modeling -rapid prototyping -observations/interviews -Star Trek/science fiction