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Usability
 
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This document was presented by Prof. Dr. Stefan Koch on 28th of November.

This document was presented by Prof. Dr. Stefan Koch on 28th of November.

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    Usability Usability Presentation Transcript

    • E-commerce Adoption and Web Usability E-Commerce 1
    • Acceptance of IS  Basic model: Technology Acceptance Model  Behavioral model  Perceived usefulness and perceived ease of use impact intention to use  Perceived ease of use also impacts perceived usefulness  Personal factors sometimes included  Mandatory use E-Commerce 2
    • Acceptance of e-commerce & e-business  Many empirical works on acceptance and choice  Main influences  Functionality  User interface  Security  Trust  Entertainment  Proposition  Community and their activity E-Commerce 3
    • Web Usability  Usability is the measure of the quality of the user's experience when interacting with a web site. A usable web site is one that enables users to complete tasks quickly, easily, and pleasantly.  Five aspects of usability (Jakob Nielsen)  Ease of learning: interface needs to allow novice users to learn it quickly to succeed in accomplishing basic tasks  Efficiency of use: interface should allow rapid accomplishment of tasks for more experienced users  Memorability: casual users of the site are assisted by an interface design that they can remember how to use  Error frequency & severity: interface should minimise number and severity of errors, and allow for quick error recovery  Subjective satisfaction: pleasant experience E-Commerce 4
    • Web Usability - Measures  Learnability = "How easy is it for users to accomplish basic tasks the first time they encounter the design?"  Task completion ~ How many users give up on a task?  Efficiency = "Once users have learned the design, how quickly can they perform tasks?"  Discoverability ~ How effective is the site at introducing additional info/features the user might be interested in?  Memorability = "When users return to the design after a period of not using it, how easily can they reestablish proficiency?"  Error recovery = "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?" E-Commerce 5
    • Web Usability - Engineering  Functionality requirements gathering  User analysis  What would the user want the system to do? How would the system fit in with the user's normal workflow or daily activities? How technically savvy is the user and what similar systems does the user already use? What interface look & feel styles appeal to the user?  Knowledge/Experiences – e.g. Computer literacy, Application experience, Task experience, Reading level, Native language / Job/Task – e.g. Frequency of use, Turnover rate, Task importance / Psychological Characteristics – e.g. Attitude, Motivation, Cognitive style / Physical Characteristics – e.g. Age, Gender, Handedness, Handicaps E-Commerce 6
    • Web Usability - Engineering  Create use scenarios to drive your design.  Example user tasks: Find information about a particular product. Learn about newest projects. Find out about future presentations. Download copy of a document.  Information architecture – development of the process and/or information flow of the system  Card sorting  Prototyping – paper prototypes or simple interactive screens  Usability testing  Graphic Interface design – actual look & feel design of the final graphical user interface E-Commerce 7
    • Web Usability – Usability Testing  Inspection  Checklist of guidelines applied to each page  Heuristic evaluation is the evaluation of the usability of a web site through the application of well-known usability principles.  Strength: Greater number of usability problems can be found at one time  Weakness: Team members are incapable of acting as objective novice users  Inquiry (surveys) of past users  Weakness: It is usually more expensive to fix problems after they go live  Mining web analytics  Weakness: Data can be misinterpreted E-Commerce 8
    • Web Usability – Usability Testing  User testing  generally the most sophisticated and costly, but usually the most useful of testing methods.  involves use of test subjects who are given a set of tasks to complete using a web interface  subjects are chosen from the site's target audience (even 5 people can give good results)  tasks based on the site's main goals and objectives  user test is monitored (video cameras and/or eyemovement tracking devices)  user talks while working  sometimes questionnaire at end (subjective feelings) E-Commerce 9
    • Web Usability - Styleguide  The guidelines for a consistent look and feel and site navigation experience.  The key to success is making the details simple, understandable, and easy to implement.  A style guide should include:  Overall navigation and organization  Templates for each “page type”  Guidelines for adding content  Guidelines for removing/archiving content  Presentation guidelines (e.g., color schemes)  Approval and workflow checklists E-Commerce 10
    • Web Usability - Guidelines  Visibility of system status  users need to know where they are in your site; the status of form transactions need to be clear - let the user know that their data submission was successful  Match between the system and the real world  speak the users' language and avoid jargon; use natural mappings (e.g. back buttons point left, forward buttons point right)  User control and freedom  provide clearly marked exits (or home buttons); support undo and redo transactions; don't take browser controls away from users E-Commerce 11
    • Web Usability - Guidelines  Consistency and standards  using navigation controls consistently; use consistent layout; author to HTML and CSS standards (improves cross-browser usability)  Error prevention  regularly check for broken links; use javascript to validate forms  Recognition rather than recall  label navigation elements (don't make people mouse over them to see what they are)  Flexibility and efficiency of use  allow advanced search options; don't prevent users from bookmarking pages (to let them enter your site at a point *they* choose); provide multiple paths to access the same information E-Commerce 12
    • Web Usability - Guidelines  Aesthetic and minimalist design  don't clutter pages with unnecessary objects as they add to download time and user confusion  Help users recognise, diagnose and recover from errors  explain errors in plain English rather than using error codes; error messages should offer a solution, or link to a solution  Help and documentation  not necessary on smaller sites, but when used, should be integrated within the site E-Commerce 13
    • Web Usability - Guidelines         Different users will use your site in different ways Web users don't read instructions Web users don't even usually read ... they scan Web users are click happy ... typically clicking on the first link that looks like it might be what they are looking for So ... don't break their back button Make your links squint-test obvious Quickly answer "Where am I, and what can I do here?" on every page (on every page Google indexes) The harder it is (or the longer it takes) the more likely users are to leave ... and even if they stay they'll use your site less E-Commerce 14
    • Web Usability - Guidelines  Every page should have:  Site ID (Where am I? What site is this?)  Page Name  Global Navigation  Local Navigation  Breadcrumbs - “You are here”  Search (if possible)  Practice "inverted pyramid" writing  Key ideas first  Supporting ideas last  Write for scanning: Headings, Bullets  Highlight Key words, Links  Short paragraphs, one idea per paragaph E-Commerce 15
    • Web Usability - Problems  Inconsistent  Poor Organization/Layout  Unexpected Occurrence of Events  http://www.webpagesthatsuck.com/  http://www.useit.com/alertbox/9605.html E-Commerce 16
    • Web Usability Monitoring E-Commerce 17
    • Web Usability Monitoring E-Commerce 18