The Importance of HCI & User Interface Design


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Jenny Le Peuple HCI and interface/interaction design: scope & importance

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What is HCI? “Human-Computer Interaction (HCI) is the study and the practice of usability. It is about understanding and creating software and other technology that people will want to use, and will find effective when used. The concept of usability, and the methods and tools to encourage it, achieve it, and measure it are now touchstones in the culture of computing” Carroll (2002)

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Origins of HCI National Bureau of Standards Conference (1982) ‘Human Factors in Computer Systems’ Emerging threads/roots: Prototyping & iterative development Software psychology & human factors User interface software Models, theories & frameworks (from cognitive science)

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Contributory disciplines After Preece (1995 p.48) Social & Organisational Psychology Cognitive Psychology Ergonomics & Human Factors Engineering Design Anthropology Sociology Philosophy Linguistics Artificial Intelligence Computer Science UID/HCI

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System Acceptability After Nielsen (1993 p.25) Usability Easy to learn Easy to remember Few errors Subjectively pleasing Efficient to use

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The user interface - simple model Proposed by Abowd & Beale 1991 - see Dix et al (1998 p. 106) user system observation INPUT articulation OUTPUT presentation performance

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Scope of the user interface Includes: design of input & output devices design of workstation environment the user/s and their characteristics tasks to be supported context of use information layout & meaning

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Input & output devices Input: keyboards pointing devices mice, joysticks, trackballs etc increasingly, voice Output: printers screen voice

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Workstation environment Ergonomics: design of hardware features screen characteristics contrast, resolution environment lighting, temperature, furniture etc

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User characteristics cognitive ability expertise/experience level of education age attitude physical ability culture

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Human senses Major Vision - seeing Audition - hearing Haptic Tactition - sense of touch, pressure Proprioception - body awareness Other Gustation - taste Olfaction -smell Thermoception - heat and cold Nociception - pain Equilibrioception - balance

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Senses and modalities In the context of HCI, modalities are concerned with: the senses that humans use to perceive outputs from a computer system devices used by computers to detect inputs from humans

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Keyboards - multiple modalities What senses are involved? And is the layout still appropriate?

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Information layout & meaning/1 After Tullis (1988) cited in Preece (1995 p. 103)

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Illustration from Isys Information Architects Which are the labels? Which are the input fields? Why is “help” text truncated? Information layout & meaning/2

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Importance of user interface In a business context: efficiency effectiveness productivity safety user satisfaction

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Usability attributes Measurable: learnability efficiency memorability minimising error user satisfaction Nielsen (1993)

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Benefits of engineering usability improved image to users higher quality end product lower costs over life of product lower initial/on-going training costs improved user efficiency/accuracy lower help-desk costs Source: NatWest Bank Usability Services

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Usability - cost benefit(s), a simple example Multiple log in scenarios: (1 minute each) Library Evision Weblearn Timetables Webmail (Staff) MIS Line One log in scenario: (1 minute) Library Evision Weblearn Timetables Webmail (Staff) MIS Line

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Usability standards ISO 9241-11 efficiency effectiveness satisfaction ISO 13407 Human Centred Design 90/270/ EEC > BS 7179/1990 - Ergonomics (Screen Display)

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Usability guidelines, one example Quesenbery (2001) expanded ISO 9241 guidelines to five dimensions - the “5 Es” Effective completeness and accuracy with which users achieve specified goals Efficient the speed (with accuracy) in which users can complete the tasks for which they use the product Engaging pleasant and satisfying to use Error tolerant prevent errors caused by the user’s interaction & help the user recover from any errors that do occur. Easy to learn allows users to build on their knowledge without deliberate effort Read the whole article at:

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Overenthusiastic use of colour Spot the difference... Illustrations from Isys Information Architects Examples of poor interfaces

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Illustrations from Isys Information Architects Examples of poor interfaces Apparently, the person is supposed to be “out”…

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Office equipment Photograph courtesy of Bad Human Factors Designs How do I make a copy?

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Which dial controls which ring? Better “mapping” Domestic appliances Photographs courtesy of Bad Human Factors Designs

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The user interface ? the point of contact between a human user and a system

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Design is a purposive activity! (has purpose) “Software design is the act of determining the user’s experience with a piece of software. It has nothing to do with how the code works inside, or how big or small the code is. The designer’s task is to specify completely and unambiguously the user’s whole experience” Liddle (1996) Good quality (i.e. effective, pleasurable to use) interfaces do not occur by accident, they happen by design …

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Reading and other activities to complete before Week 3 Read Chapter 2 of Le Peuple & Scane (2003), User Interface Design, and attempt the “Quick Tests”. Read Quesenbery, W. (2001). What Does Usability Mean: looking beyond ‘ease of use’. Proceedings of Society for Technical Communication Conference, 2001. Pre-publication article available at: Visit

Summary: An introduction to the concepts of Human-Computer Interaction and User Interface Design.

Tags: usability user-interface-design hci