Creating User Interfaces

Usability Rules. Fitts's Law

Homework: Complete comparison of sites to present next class.

Assignment

• Next Monday, present comparison of sites• This is like the college comparison.• YOU need to

– Identify two similar sites– Design/formulate the task to be done

• Getting information and/or• Entering information

– You don’t have to buy anything or make any commitments

– Do it and report on usability.

Today

• Make teams of two.• Post proposal to Proposals Forum.

– One proposal per team.– Proposal can be general, without identifying the

sites, but the more specific the better.– I will approve or suggest change.

• Monday: present in class.– Show sites. Talk about results.– 1-pager.

State of the Union

• Reactions to enhanced presentation ??

• Articles on use of Twitter, other.– Administration– Republicans

Aside• Much of computing, including building

interfaces and assessing usability, was aimed at– ‘in-house’ applications, e.g., tools for

manufacture of products– ‘in-house’ applications where trained staff

person did task for customer or client– Products to be used by professionals

• Now, these still exist, but there is more…

Today’s applicationsNon-professionals using computer applications (on computers or devices)

•Buying or arranging for services– Goods – Affordable Care Act

•Selling

•Banking, stocks, etc.

•Research

– Academic, travel, etc.

•Games

•Doing their jobs

– Teachers arranging rooms, equipment, submitting grades

What’s the difference?• Different levels of training, from nothing to

need to accommodate experienced user• Need to react to expectations of how other

applications work• Mix of objectives

– Keep person on site happy so they can see ads

– Complete transaction AND keep person happy– ?

Multiple devices

• Applications that are web sites may need to be usable on different types of devices– Touch and/or mouse– Different screen dimensions– Different environments– NOTE: not all applications are web sites!!!

• Sometimes at the same time!

ISO definition

usability of an interface is "the effectiveness, efficiency, and satisfaction with which specified users can achieve specified goals in a particular environment". – effectiveness=does it do the job– efficiency=how well it does it in terms of time,

effort, costs (system & user) other factors– satisfaction=perception of user

Nielson Norman Group

Usability is defined by 5 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?

Another definition

• Jakob Nielsen's rules: http://www.useit.com/papers/heuristic/heuristic_list.html

• Heuristics for mobile phones: http://www.iphoneuxreviews.com/?p=114

• Yours?

Error prevention

• I also call this offensive practices as opposed to defensive: keep error from happening

• Examples:– Entering critical data twice– pull-down lists of months, days, years, rather

than open text. Can also force dates in the future– dulling/fading illegal options– ???

Error recovery

• Errors do happen. Make detection early, quick, efficient– catch as many errors as possible each time,

not one at a time IF POSSIBLE– Use confirmation screens

Current NY voting machines

• People mark ballots (fill in the circle) and• feed into optical readers.• Advantage: paper record.• Disadvantages:

– no confirmation– whole ballot can be rejected if over-voting (but

no clue as to what)– less than private– ?

Adaptability

• Provide alternatives for new versus experienced users. Examples:– shortcut keys on many applications– reduced menus (AutoCad example)– ?

Recognition versus recall

• Show list of recent and/or most popular choices, changed as user types so user can select.

• ?

Fitts's Law

Time to get to a place on the screen is dependent on the distance and the precision required.

Confirmed by actual testing!

T = k log2(D/S + 0.5), k ~ 100 msec.

T = time to move the hand to a target D = distance between hand and target S = size of target

http://www.usabilityfirst.com/glossary/term_265.txl

http://ei.cs.vt.edu/~cs5724/g1/glance.html

Group exercise

• http://www.asktog.com/columns/022DesignedToGiveFitts.html

Cautionary note

• Skills at using screen, mouse, touch pad, etc. changing, evolving

• Skill at typing (regular) text is….degrading?– Discuss

Predictive text

• Opinions? What do you generally do?

• Some predictive text is adaptive….

Reprise: Stories• People coming into ER complaining of

abdominal pain– Researcher did not want natural language– best/satisfactory interface MAY be different than

automation of manual method– interface needs to fit the data/problem.

• Early IBM multimedia lessons (Ulysses, Columbus, etc.)– Complaints of system too slow, but wasn't it more lack

of keywords, descriptions, etc. leading to the wrong video clip.

– Case of 'advanced technology' not being as effective as other methodology.

Also: expectations / experiences

• What users bring to [your] application is important:– Experiences with other (existing) platforms

and applications– Expectations on what [your thing] will be

• For example, this should take one mouse click versus

• I need to enter considerable amount of complex data. The process can and should be … deliberate, much feedback.

Classtime / Homework

• Complete comparison of sites to present in class– Sites must be comparable!– Identify goals of users (distinct users) and

owners.– Usability definition(s):

• effectiveness, efficiency, satisfaction• Other definitions?

– Think about errors and recovery.– Prepare 1-pager

1-pager• [required in most of my classes.]• An abstract = a summary of your findings.

– NOT everything: just the most important.– Formal writing, often passive voice.– Proofread.– Consider use of italics, bold.

• Relevant images• Sources: in this case, the two sites, in PROPER

format, not just the URL, include dates