DOC PREVIEW
UMD CMSC 434 - Design Principles and Usability Heuristics

This preview shows page 1-2-3 out of 8 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 8 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 8 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 8 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 8 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

Design Principles and Usability Heuristics 1Ben Bederson / Saul GreenbergDesign Principles and Usability Heuristics - Part IYou can avoid common design pitfalls by following 9 design principlesYou can inspect an interface for usability problems with these principlesBen Bederson / Saul GreenbergDesign principles and usability heuristics (I)Broad “rules of thumb” that describe features of “usable” systemsDesign principles• broad usability statements that guide a developer’s design efforts• derived by evaluating common design problems across many systemsHeuristic evaluation• same principles used to “evaluate” a system for usability problems• becoming very popular- user involvement not required- catches many design flaws• is an “expert review”Design Principles and Usability Heuristics 2Ben Bederson / Saul GreenbergDesign principles and usability heuristics (II)Advantages• the “minimalist” approach- a few general guidelines can correct for the majority of usability problems- easily remembered, easily applied with modest effort• discount usability engineering- cheap and fast way to inspect a system- can be done by usability expertsDisadvantages:• principles can’t be treated as a simple checklist• subtleties involved in their useBen Bederson / Saul GreenbergDiscount Usability EngineeringCheap• no special labs or equipment needed• the more careful you are, the better it getsFast• on order of 1 day to apply• standard usability testing may take weeksEasy to useDesign Principles and Usability Heuristics 3Ben Bederson / Saul GreenbergHeuristic EvaluationDeveloped by Jakob NielsenHelps find usability problems in a UI designSmall set (3-5) of evaluators examine UI• independently check for compliance with usability principles(“heuristics”)• different evaluators will find different problems• evaluators only communicate afterwards- findings are then aggregatedCan perform on working UI or on sketchesBen Bederson / Saul GreenbergHeuristic Evaluation ProcessEvaluators go through UI several times• inspects various dialogue elements• compares with list of usability principles• consider other principles/results that come to mindUsability principles• Nielsen’s “heuristics”• supplementary list of category-specific heuristics- competitive analysis & user testing of existing productsUse violations to redesign/fix problemsDesign Principles and Usability Heuristics 4Ben Bederson / Saul GreenbergPhases of Heuristic Evaluation1) Pre-evaluation training• give evaluators needed domain knowledge and information on thescenario2) Evaluation• individuals evaluate and then aggregate results3) Severity rating• determine how severe each problem is (priority)4) Debriefing• discuss the outcome with design teamBen Bederson / Saul GreenbergHow to Perform EvaluationAt least two passes for each evaluator• first to get feel for flow and scope of system• second to focus on specific elementsIf system is walk-up-and-use or evaluators are domain experts, then noassistance needed• otherwise might supply evaluators with scenariosEach evaluator produces list of problems• explain why with reference to heuristic or other info.• be specific and list each problem separatelyDesign Principles and Usability Heuristics 5Ben Bederson / Saul GreenbergExamplesCan’t copy info from one window to another• violates “Minimize the users’ memory load”• fix: allow copyingTypography uses mix of upper/lower case formats and fonts• violates “Consistency and standards”• slows users down• probably wouldn’t be found by user testing• fix: pick a single format for entire interfaceBen Bederson / Saul GreenbergSeverity RatingUsed to allocate resources to fix problemsEstimates of need for more usability effortsCombination of• frequency• impact• persistence (one time or repeating)Should be calculated after all evaluations are inShould be done independently by all judgesDesign Principles and Usability Heuristics 6Ben Bederson / Saul GreenbergSeverity Ratings (cont.)1 - cosmetic problem2 - minor usability problem3 - major usability problem; important to fix4 - usability catastrophe; imperative to fixBen Bederson / Saul GreenbergDebriefingConduct with evaluators, observers, and development team membersDiscuss general characteristics of UISuggest potential improvements to address major usability problemsDevelopment team rates how hard things are to fixMake it a brainstorming session• little criticism until end of sessionDesign Principles and Usability Heuristics 7Ben Bederson / Saul GreenbergResults of Using HEDiscount: benefit-cost ratio of 48 [Nielsen94]• cost was $10,500 for benefit of $500,000• value of each problem ~15K (Nielsen & Landauer)• how might we calculate this value?- in-house −> productivity- open market −> salesCorrelation between severity & finding w/ HEBen Bederson / Saul GreenbergWhy Multiple Evaluators?Single evaluator achieves poor results• only finds 35% of usability problems• 5 evaluators find ~ 75% of usability problems• why not more evaluators???? 10? 20?- adding evaluators costs more- many evaluators won’t find many more problemsDesign Principles and Usability Heuristics 8Ben Bederson / Saul GreenbergWhy Multiple Evaluators (cont)?problems found benefits / cost(Graphs for a specific example)Ben Bederson / Saul GreenbergThree Evaluation Methods:• Usability analysis with users (previously discussed)- Interviews- Questionnaires- Silent observation- Think aloud- Constructive interaction• Discount methods such as Heuristic Evaluation- Discussion of the technique (this set of notes)- 9 heuristics (associated set of notes)• Controlled studies (touched on previously, continued


View Full Document
Download Design Principles and Usability Heuristics
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Design Principles and Usability Heuristics and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Design Principles and Usability Heuristics 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?