1. U SABILITY T ESTING

2. Software Quality Flexibility Adaptability Readability Testability Portability Reusability Interoperability Expandability Accountability Understandability Legibility Maintainability Reliability Efficiency Integrity Correctness Maturity Analyzability Operability Changeability Adaptability Stability Installability Replaceability Learnability Traceability Usability

3. Perform better in demos and reviews, users more receptive Are easier for first-time users to learn and use, reducing support costs Characteristics of Usable Products: Increase corporate user acceptance of internally developed systems Increase customer satisfaction and loyalty, increasing product use. What is Usability ? Usability is the “effectiveness, efficiency and satisfaction with which a specified set of users can achieve a specified set of tasks in a particular environment ISO Definition: How easy is it to learn a system ? How efficiently can the users use the system once they have learned to use it ? Is the system pleasant to use ? How frequent are errors made and how serious are they ? Is it easy to remember what to do ?

4. Usability Problems ? Usability problems are aspects of the user interface that may cause the system to have reduced usability. Characteristics of the product that make it difficult or unpleasant for users to accomplish tasks supported by the product Problem Severity: The frequency with which the problem occurs. Is it common or rare? The impact of the problem if it occurs. Will it be easy or difficult for the users to overcome? The persistence of the problems : Is it a one-time event that users can deal with once they know how or will they repeatedly be bothered by the problem? The market impact. What will the impact be on the popularity of the product?

5. Usability Evaluations User Testing empirical method of allowing end-users to use the system under monitoring of usability engineers who record the users reactions and problems. User Testing empirical method of allowing end-users to use the system under monitoring of usability engineers who record the users reactions and problems. Usability Inspections evaluations performed normally by usability specialists (some methods incorporate users and developers) who make a more detailed evaluation of the interface. Types include: 1. Heuristic Evaluations 2. Pluralistic Walkthroughs 3. Consistency Inspections 4. Standards Inspections 5. Cognitive Walkthroughs Usability Inspections evaluations performed normally by usability specialists (some methods incorporate users and developers) who make a more detailed evaluation of the interface. Types include: 1. Heuristic Evaluations 2. Pluralistic Walkthroughs 3. Consistency Inspections 4. Standards Inspections 5. Cognitive Walkthroughs

6. User Testing Users performing real task with a real systemUsers must be a true representation of the target usersEvaluators video record the users throughout the evaluation and can see what the users are experiencing Good at finding major problems and task related problemsUsers are likely to miss minor problems

7. Cognitive Walkthrough Focus is the ease of learning aspect of usability Provides limited benefits when compared to other methodsBased on the theory of learning by explorationCan be used early in the design process

8. Pluralistic Walkthroughs Group activity involving developers, users, and human factors specialists work work through scenarios while discussing the usability issues associated with the interface. Can only evaluate one course of action using the hardcopy medium Can be used early in design with storyboards or mockups

9. Standards Inspections Evaluation of an interface to determine compliance with a given standard such as OSF/Motif Not related to tasks nor scenarios Uncovers such things as misplacement of menu items, failure to provide tabbing between groups in dialogue boxes or as in the examples below the misuse of wrong controls Misuse of Control Functions: Project Manager insisted that drop-down controls be used to collect information whenever possible due to his fear that some 400,000 corporate users were incapable of typing. The result was the following: Misuse of Control Functions: Project Manager insisted that drop-down controls be used to collect information whenever possible due to his fear that some 400,000 corporate users were incapable of typing. The result was the following:

10. Standards Inspections (cont) Misuse of Controls: In this example the developer should have used a drop-down controls. This type of interface is very inefficient for the user and makes the application slower while using more memory. Makes you wonder how the user would select his country and city? Misuse of Controls: In this example the developer should have used a drop-down controls. This type of interface is very inefficient for the user and makes the application slower while using more memory. Makes you wonder how the user would select his country and city?

11. Consistency Inspections Evaluation of the consistency across various parts of the product or product family Distributed and segregated work results in developers making decisions on everything from terminology to placement of icons, window etc Goal is to have the maximum level of consistency throughout the product or product family so users will be able to quickly learn how to use the system and find using the system easy

12. OK HelpCancel OK Help Cancel OK Help Cancel OK HelpCancel How Many Differences Can You Spot ? Answer: Location Boxed OK Underlined H Answer: Location Boxed OK Underlined H

13. Heuristic Evaluation Guidelines or (Heuristics) used to judge the interface’s usabilityOne of the “discount usability engineering” methodsMethod can be used in early stages of design using storyboards, screen printouts or prototypes Evaluators inspect the interface on their own

14. Common Heuristics Visibility of system status User control and freedom Consistency and standardsHelp and documentation Error prevention Aesthetic and minimalist design Flexibility and efficiency of use

15. Irrelevant information should be deleted Too much information. Can anyone spot the other error? Where’s the ‘HELP’ button they say to press?

16. Common Heuristics Match between system and the real world Visibility of system status User control and freedom Consistency and standards Help and documentation Error prevention Aesthetic and minimalist design Flexibility and efficiency of use Recognition rather than recall

17. Geekspeak and System-Orientated Terms How would a user know what to select ? Problem using the RGB hexadecimal numbers to represent the colour selection to the user. This is an Internet Explorer window that lets users set the formatting for headers and footers printed from the browser. I am sure you all know what the sample specifies.

18. Common Heuristics Help user recognize, diagnose and recover form errors Match between system and the real world Visibility of system status User control and freedom Consistency and standards Help and documentation Error prevention Aesthetic and minimalist design Flexibility and efficiency of use Recognition rather than recall

19. Error Messages Should be Meaningful

21. Miscellaneous Points Group vs Individual Evaluators Individual evaluators have been shown to uncover approximately 35% of the usability errors Optimum number varies between 3 and 5 What Method Should I Use ? No single method will find all usability problems Use a combination of complementary methods

22. Miscellaneous Points When Should I Evaluate The earlier the better Iteratively Developer “Buy-In” Seeing is believing - Video tape user tests Incorporate the developer into the evaluation process

23. What’s in it for Me ? Usability problems cost money to fix. The earlier they are discovered the less they cost to fix A more usable product is a better product and a better product will be better accepted and make more money If you can’t afford the time and resources to do it right can you afford the time and resources do do it over?

24. Conclusion Usability is an aspect of Software Quality. Usability is defined as the ease at which user learn and use the system coupled with the overall experience they have with the product. Usability problems are problems that adversely effect the usability of the product. Usability can be assessed by User Testing and Usability Inspection. The best approach is to use both User testing and Usability Inspections throughout the development cycle to improve the quality of the product