HCI Usability: Measurement PDF

Lecture 3: Usability: Measurement 1  Nielsen’s 10 Usability Heuristics for User Interface Design Developed by Jakob Nielsen: 1. Visibility of system status 2. Match between system and real world 3. User control and freedom 4. Consistency and standards 5. Er...

Lecture 3: Usability: Measurement 1  Nielsen’s 10 Usability Heuristics for User Interface Design Developed by Jakob Nielsen: 1. Visibility of system status 2. Match between system and real world 3. User control and freedom 4. Consistency and standards 5. Error prevention 6. Recognition rather than recall 7. Flexibility and efficiency of use 8. Aesthetic and minimalist design 9. Help users recognise, diagnose and recover from errors 10. Help and documentation 2 1- Visibility of System Status The system should always keep users informed about what is going on through feedback within reasonable time. 3 4 2- Match Between System and Real World The system should speak the users' language, with words, phrases and concepts familiar to the user not system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order. 5 Example: Match Between System and Real World 6 7 3- User Control and Freedom Users often choose system functions by mistake They will need a clearly marked "emergency exit" to leave the unwanted state without having to go through an extended dialogue Example: Support undo and redo. 8 “Reset stats 9 4- Consistency and Standards (metaphor) Users should not have to wonder whether different words, situations, or actions mean the same thing Follow platform conventions 10  Too much of a good thing? Google’s previous version of the Mail, Calendar, and Drive icons (top) had a consistent visual style, but have recently been updated (bottom) to use the same colors across several applications. When viewed at a small size, as is typical on mobile devices, the similarities between these icons will make them hard to differentiate. 11 Metaphor interface design ( user’s familiar knowledge) an interface metaphor is a set of user interface visuals, actions and procedures that exploit specific knowledge that users already have of other domains. The purpose of the interface metaphor is to give the user instantaneous knowledge about how to interact with the user interface. Example: desktop metaphor, web portals 12 Benefits of interface metaphors Makes learning new systems easier Helps users understand the underlying conceptual model Can be very innovative and enable the realm of computers and their applications to be made more accessible to a greater diversity of users Problems with interface metaphors Conflict with design principles and a problem space Forces users to only understand the system in terms of the metaphor Designers can inadvertently use bad existing designs and transfer the bad parts over Limits designers’ imagination in coming up with new conceptual models Interface metaphor design Evaluate metaphors: How much structure does it provide? How much is relevant to the problem? Is it easy to represent? Will the audience understand it? 14 5- Error Prevention In simple terms, prevent the occurrence of the errors or any situation that leads the user to make a false or any unwanted decision. 15 16 6- Recognition Rather Than Recall 1. Recognition It means recognizing the information, thing, or event as familiar in our memory. 2. Recall It means to retrieve the related information from the memory. 17 6- Recognition Rather Than Recall Make objects, actions, and options visible The user should not have to remember information from one part of the dialogue to another Instructions for use of the system should be visible or easily retrievable whenever appropriate 18 19 7- Flexibility and Efficiency of Use Shortcuts— unseen by the novice user — speed up the interaction for the expert users such that the system can cater to both inexperienced and experienced users. 20 8- Aesthetic and Minimalist Design Dialogues should not contain information which is irrelevant or rarely needed Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility. 21 9- Help Users Recognise, Diagnose and Recover from Errors Error messages should: be expressed in plain language (no codes) precisely indicate the problem constructively suggest a solution 22 10- Help and Documentation it is necessary to provide help and documentation Any such information should: be easy to search be focused on the user's task list concrete steps to be carried out not be too large 23 Case study? A study of “usability of university web site” The purpose of this study is to discuss the usability of designing a university-wide student information system, it is necessary to meet the usability requirements of various groups, including Nielsen’s 10 Usability Heuristics for User Interface Design