Transcript Slides
After testing users Compile Data Summarize Analyze Develop recommendations Produce final report Compile Data Compile data as you test Speeds up overall analysis Transfer hand written notes to computer Record data that is fresh in you mind Do it each data of testing Creating Summaries Create descriptive summaries Quantitative data Transfer information into summary sheets Allows you to see patterns Summarize Performance Data Summarize performance data in terms of: Task timings Task accuracy Task Timings How much time users required to complete a task Mean time to complete Median time to complete Range of completion times Standard deviation of completion times Mean time to complete Average time to complete task: Sum of all Completion Times mean = ------------------------------Number of Participants Mean time to complete Gives a rough indication of how the group performed Can be used to determine if user did better or worst If task time are very skewed then use: Median time to complete Median time to complete Time that is exactly in the middle position when all are listed in ascending order Range of completion times Shows highest and lowest completion times for each task Very revealing if there is a huge difference Might be affected by user’s experiance Standard deviation Measures range of variability How times differ from one another Task Accuracy Count of number of errors Three common ones: % of users performing successfully within time benchmark % of users performing successfully % of users performing successfully including those who required assistance Summarize Preference Data For limited choice questions: Sum counts of number chosen For free form questions: List all questions and group similar answers Summarize Preference Data Produce mean scores of Semantic Differentials: Simple 3 2 1 0 1 2 3 Complex 1 2 3 4 5 6 7 Other measures # of times help was accessed # of times manual # of points of hesitation Analyze Data Begin analysis with the tasks users had th most problem with Keep focused on the worst problems Analyze Data Id and focus on tasks that did NOT meet criteria Example: 70% did not complete task A Label this a problem Analyze Data Id user errors and difficulties Conduct a source of error analysis Some will be obvious Some will be very subtle Problem Analysis Prioritize problems by criticality: Criticality = Severity + Probability of Occurrence Severity Ranking Frequency Ranking Develop Recommendations Translates data and summaries into recommendations Final step before generating report Take break from processes for a few days Recommendations Difference perspective are essential Need a buy-in Focus on solutions with the widest impact Also consider global usability issues Recommendations Ignore “Political Considerations” Short and Long term recommendations Indicate areas where further research is needed Be thorough Usability Report Provide solutions Be specific Clearly state the recommendation Usability Report Short Easy to read Communicate findings Usability Report Sections: Executive Summary Method Section Results Findings and recommendations Appendices Memory Usability affected by how we remember Capability of memory Limitations of memory Memory What we remember and how we can apply what we already know Highly variable Memory Based on model of human memory: Memory Short-Term memory is small Long-Term memory stores large amount but fallible Memory Chunking Break large data into smaller more recallable chunks SSN vs Drivers license number URL Design Mental Models How users use memory to understand new experiences Mental models used to make predictions of how a system works Can lead to usability issues Bad Designs Conceptual Models Can understand how it works because you build a simulation in your head and simulate it operation Three parts: Constraints Affordances Mappings Constraints Helps users by restricting behaviors Constraints: Physical Semantics Cultural Logical Affordances Defines possible: Uses Actions Functions Understand how something works based on appearance Affordances Good affordances enable user to use just by looking No: Label Icon Instructions Affordances Mapping Relationship between actions and results Controls and their effects System state and what is visible Bad Mapping Mental Models Design Model User Model System Model Mental Models Mental Model Metaphors Help guide mental model choice Speeds the learning process Brittle Do not expand very well Information Architecture Helps users find information quickly and easily Poor information architecture make users confused, frustrated, and angry Defines mapping between what a site is and how it will work Information Architecture Information Architecture Information Architecture Matter of Perspective Content Organization Major component of user-centered design Major issue with web sites Deals with user’s biggest complaint: “I can’t find what I am looking for.” Content Organization Two levels of searching: Can’t find it on the web (search engines) Can’t find it on site (site organization) Creates foundation for effective site navigation Organizational Systems Schemes Structures Organizational Schemes Classification scheme for content items How to cluster items into groups Scope of content Organizational Structures Determines relationships between groups Method of grouping items Organizational Schemes Taking a drink from a fire hose Question becomes how to organize information into categories which are logically consistent Part of every day life Organizational Schemes Two categories of organization schemes: Exact Ambiguous Exact Schemes Divides information into mutually exclusive groups Category Time Location Alphabet Continuum Content Organization Organizational Schemes Organizational Schemes Organizational Schemes Organizational Schemes Organizational Schemes Organizational Schemes