To be covered:- What is HCI? Goal of HCI HCI - An Interdisciplinary Area Concerns in HCI

1. To be covered:- • What is HCI? • Goal of HCI • HCI - An Interdisciplinary Area • Concerns in HCI • Interface and interaction design • Goals of interaction design • Utility, Usability, Likeability • Structured Process for Creating Usable Products • Principles to support usability • How to Achieve Usability

2. Human Computer Interaction (HCI) Human–computer Interaction (HCI) involves the study, planning, and design of the interaction between people (users) and computers. Interaction between users and computers occurs at the user interface (or simply interface), which includes both software and hardware. Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them”

3. Human Computer Interaction (HCI) Because human–computer interaction studies a human and a machine in conjunction, it draws from supporting knowledge on both the machine and the human side. On the machine side, techniques in computer graphics, operating systems, programming languages, and development environments are relevant. On the human side, communication theory, graphic and industrial design disciplines, linguistics, social sciences, cognitive psychology, and human factors such as computer user satisfaction are relevant.

4. Goal of HCI • A basic goal of HCI is to improve the interactions between users and computers by making computers more usable and receptive to the user's needs. Specifically, HCI is concerned with: • Methodologies and processes for designing interfaces (i.e., given a task and a class of users, design the best possible interface within given constraints, optimizing for a desired property such as learnability or efficiency of use). • Methods for implementing interfaces (e.g. software toolkits and libraries; efficient algorithms). • Techniques for evaluating and comparing interfaces. • Developing new interfaces and interaction techniques. • Developing descriptive and predictive models and theories of interaction.

5. The Goals of HCI To Produce

6. In order to produce computer system with good usability; Developers must attempt to The long term goal: To design systems that minimize the barrier between the human’s cognitive model of what they want to accomplish and the computer’s understanding of the user’s task

7. HCI - An Interdisciplinary Area/ Disciplines that Contribute to HCI • Computer Science • Application design and engineering of human-computer • Interfaces • Psychology • The application of theories of cognitive processes and • the empirical analysis of user behavior • Sociology and Anthropology • Interactions between technology, work, and organization • Design and Industrial Design • Creating interactive products

9. Concerns in HCI Science, Engineering, and Design Aspects • The joint performance of tasks by humans and machines • The structure of communication between human and • machine • Human capabilities to use machines (including the • learn ability of interfaces) • Algorithms and programming of the interface itself • Engineering concerns that arise in designing and • building interfaces • The process of specification, design, and implementation • of interfaces

10. Interface and interaction design • Interface design (ID) • • Primarily design of 2D/3D widgets • Designing interactive products to support people • in their everyday and working lives • • Sharp, Rogers and Preece (2002) • The design of spaces for human communication • and interaction • • Winograd (1997)

11. Goals of interaction design • Develop usable products • Usability means: • • easy to learn • • effective to use • • enjoyable experience • Usable products = successful products? • Involve users in the design process

12. Utility, Usability, Likeability • Utility • a product can be used to reach a certain goal or to • perform a certain task. This is essential! • Usability • relates to the question of quality and efficiency. E.g. how • well does a product support the user to reach a certain • goal or to perform a certain task. • Likeability • this may be related to utility and usability but not • necessarily. People may like a product for any other • reason…

13. What is Usability “Usability is a quality attribute that assesses how easy user interfaces are to use. The word ‘usability’ also refers to methods for improving ease-of-use during the design process.” • Usability has five quality components: • Learn ability: How easy is it for users to accomplish basic tasks • the first time they encounter the design? • Efficiency: Once users have learned the design, how quickly • can they perform tasks? • Memorability: When users return to the design after a period of • not using it, how easily can they reestablish proficiency? • Errors: 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?

14. USABILITY

15. Why is Usability Important

16. Why Usability is Important? How many systems are easy, effortless, and enjoyable to use?

17. Why is Usability Important? • Improving usability can • • increase productivity of users • • reduce costs (support, efficiency) • • increase sales/revenue (web shop) • • enhance customer loyalty • • win new customers

18. Why is Usability Important in the • Context of WWW and New Media? • Competition is very close (just another link…) • User Interface is often the central discriminating factor • Comparison is easily possible • Example – Online-Shop • Direct correlation between usability and sales is reported in many cases. • Users who can’t find the product in the shop can not buy it. • Users who are not able to fill in correctly the order form are not going to buy.

19. HCI is Central to the Design and Development Process • … even if done unconsciously. Decisions made • in the development process are likely to influence how a product can be used. • thinking about the user interface when a first • version of a product is finished is to late! • good user interfaces – and often good products • – are a joined effort of all participants in the • design and development process

20. Structured Process for Creating Usable Products • Precondition • • Understanding how people interact with their environment • • Understanding the capabilities and limitations of users • • Basic ergonomics • Analyze what interaction is required and what technical • options are available in a user centered way, evaluate • the results of the analysis • Design and prototype user interfaces with user • involvement, evaluate prototypes • Implement an interactive digital product • Test and study the product created • Usability Engineering is a part of the overall development • The process is iterative (overall and at each step)

21. Evolution of the Software Development Process

22. How it does NOT work • Usability tests at the end when the product is • ready and needs to be shipped. • Designing a new and pretty skin to a product. • Introducing HCI issues after the system • architecture and the foundations are completed. • Comparison: An interior designer can not make • a great house if the architect and engineers forgot windows, set the doors at the wrong locations, and created an unsuitable room layout.

23. Principles to support usability Learnability the ease with which new users can begin effective interaction and achieve maximal performance Flexibility the multiplicity of ways the user and system exchange information Robustness the level of support provided the user in determining successful achievement and assessment of goal-directed behaviour

24. Principles of learnability Predictability • determining effect of future actions based on past interaction history • operation visibility Synthesizability • assessing the effect of past actions • immediate vs. eventual honesty

25. Principles of learnability (ctd) Familiarity • how prior knowledge applies to new system • guessability; affordance Generalizability • extending specific interaction knowledge to new situations Consistency • likeness in input/output behaviour arising from similar situations or task objectives

26. Principles of flexibility Dialogue initiative • freedom from system imposed constraints on input dialogue • system vs. user pre-emptiveness Multithreading • ability of system to support user interaction for more than one task at a time • concurrent vs. interleaving; multimodality Task migratability • passing responsibility for task execution between user and system

27. Principles of flexibility (ctd) Substitutivity • allowing equivalent values of input and output to be substituted for each other • representation multiplicity; equal opportunity Customizability • modifiability of the user interface by user (adaptability) or system (adaptivity)

28. Principles of robustness Observability • ability of user to evaluate the internal state of the system from its perceivable representation • browsability; defaults; reachability; persistence; operation visibility Recoverability • ability of user to take corrective action once an error has been recognized • reachability; forward/backward recovery; commensurate effort

29. Principles of robustness (ctd) Responsiveness • how the user perceives the rate of communication with the system • Stability Task conformance • degree to which system services support all of the user's tasks • task completeness; task adequacy

30. How to Achieve Usability • Identify what utility and usability for the product means • • main purpose of the product • • anticipated users, target audience • • compare with similar/competing products (if applicable) • Common effort in the design and development process • • trade-offs between design, engineering, and usability • Iterative evaluation • • usability testing with different methods at various stages of the • development process • Improvement after product release • • monitoring user behavior. • • evaluation of changes to the product (e.g. adding a new feature • to a web shop)

31. Design principles • When evaluating a current user interface, or designing a new user interface, it is important to keep in mind the following experimental design principles: • Early focus on user(s) and task(s): Establish how many users are needed to perform the task(s) and determine who the appropriate users should be; someone who has never used the interface, and will not use the interface in the future, is most likely not a valid user. In addition, define the task(s) the users will be performing and how often the task(s) need to be performed. • Empirical measurement: Test the interface early on with real users who come in contact with the interface on an everyday basis. Keep in mind that results may be altered if the performance level of the user is not an accurate depiction of the real human-computer interaction. Establish quantitative usability specifics such as: the number of users performing the task(s), the time to complete the task(s), and the number of errors made during the task(s).

32. Iterative design: After determining the users, tasks, and empirical measurements to include, perform the following iterative design steps: • Design the user interface • Test • Analyze results • Repeat • Repeat the iterative design process until a sensible, user-friendly interface is created

33. Design methodologies