1. CHAPTER -7 Design Rules
1.1. Designing for maximum usability – the goal of interaction design
1.1.1. 1. Principles of usability
1.1.1.1. They provide a general understanding of usability
1.1.1.2. - abstract design rules - low authority - high generality
1.1.1.3. Principles are derived from knowledge of the psychological, computational and sociological aspects of the problem domains. They are largely independent of the technology; They depend to a much greater extent on a deeper understanding of the human element in the interaction. They can therefore be applied widely but are not so useful for specific design advice.
1.1.1.3.1. A designer will have less of a need to know the underlying theory for applying a standard. However, since standards carry a much higher level of authority, it is more important that the theory underlying them be correct or sound.
1.1.2. 2. Standards and guidelines
1.1.2.1. They are directions for design
1.1.2.1.1. Standards
1.1.2.1.2. Guidelines
1.1.3. 3. Design patterns
1.1.3.1. capture and reuse design knowledge
1.1.4. Questions
1.1.4.1. 1. What are the differences between design principles, standards, and guidelines in user interface design?
1.1.4.1.1. Principles are abstract design rules, with high generality and low authority. Standards are specific design rules, high in authority and limited in application, whereas guidelines tend to be lower in authority and more general in application.
1.1.4.2. 2. How do design standarts work across systems and applications?
1.1.4.2.1. Design standards foster a cohesive, familiar, and accessible experience across different systems and applications, benefiting both users and developers.
1.1.4.3. 3. What is the role of design rules in the early stages of the design process?
1.2. Principles to support usability
1.2.1. Learnability
1.2.1.1. the ease with which new users can begin effective interaction and achieve maximal performance
1.2.1.2. Learnability ensures that new users can work effectively and achieve maximum performance. Novice users are novices to the system. The system can help users understand how to use the system. It can maximize their performance in using the system.
1.2.1.3. Principles of learnability
1.2.1.3.1. Predictability
1.2.1.3.2. Synthesizability
1.2.1.3.3. Familiarity
1.2.1.3.4. Generalizability
1.2.1.3.5. Consistency
1.2.2. Flexibility
1.2.2.1. the multiplicity of ways the user and system exchange information
1.2.2.2. Flexibility refers to the multiplicity of ways in which the end user and the system exchange information.
1.2.2.3. Principles of flexibility
1.2.2.3.1. Dialog initiative
1.2.2.3.2. Multi-threading
1.2.2.3.3. Task migratability
1.2.2.3.4. Substitutivity
1.2.2.3.5. Customizability
1.2.3. Robustness
1.2.3.1. the level of support provided the user in determining successful achievement and assessment of goal-directed behaviour
1.2.3.2. The robustness of a system is concerned with the features that support the user in successfully achieving and evaluating goals in the system.
1.2.3.3. Principles of robustness
1.2.3.3.1. Observability
1.2.3.3.2. Recoverability
1.2.3.3.3. Responsiveness
1.2.3.3.4. Task conformance
1.2.4. Questions
1.2.4.1. 1. What does the principle of flexibility allow users to do?
1.2.4.1.1. The principle of flexibility allows users to interact with a system in various ways, giving them multiple options for completing tasks. This can include supporting different input methods (e.g., mouse, keyboard, touch), offering customizable interfaces, and enabling users to perform the same action through different paths, enhancing adaptability and personalization in their interactions.
1.2.4.2. 2. List three design principles that allow designers to create efficient and user-friendly systems?
1.2.4.2.1. Learnability Flexibility Robustness
1.2.4.3. 3. What are the three main categories of principles to support usability? Give three examples.
1.2.4.4. 4. What are the key principles that support usability in design according to Chapter 7?
1.2.4.4.1. The key principles for supporting usability include learnability, flexibility, and robustness. These principles guide the design process by ensuring that systems are easy to learn, adaptable to user needs, and able to recover from errors effectively.
1.2.4.5. 5. How do standards differ from guidelines in interface design?
1.2.4.5.1. In interface design, standards are established, formal rules or criteria that must be followed to ensure consistency and compatibility across systems. They are often mandatory and defined by organizations or governing bodies (e.g., ISO standards). Guidelines, on the other hand, are recommendations or best practices that offer designers flexibility. They provide general advice for improving usability but are not strictly enforced, allowing designers to adapt them based on the specific context of their project.
1.2.4.6. 6. Which principle is concerned with the user's ability to initiate actions towards the system?
1.2.4.6.1. - The principle related to the user's ability to initiate actions on the system is control or user control. - This principle makes users feel responsible for the system It allows them to freely initiate and manage their actions, such as starting, pausing, or canceling processes. - It emphasizes giving users the power to control the flow of interaction.
1.2.4.7. 7. How does the principle of learnability support the usability of interactive systems?
1.2.4.7.1. The principle of learnability ensures that users can quickly understand how to use the system, especially when they are first introduced to it. Thus, it supports the usability of interactive systems. A system with good learnability minimizes the time and effort required for users to become proficient, making it easier to adopt and reducing frustration. This helps users complete tasks efficiently with minimal training or assistance.
1.2.4.8. 8. Explain the principle of predictability and its importance in interface design.
1.2.4.8.1. The principle of predictability in interface design refers to allowing users to predict the outcomes of their actions based on previous interactions. It helps users understand what will happen when they perform an action. It reduces confusion and errors. Predictability increases user confidence and efficiency by making the system’s behavior consistent and reliable. When users can predict outcomes, they feel more in control and can complete tasks more quickly and effectively.
1.2.4.9. 9. What is the significance of the principle of generalizability in user interaction?
1.2.4.9.1. .
1.2.4.10. 10. What role does consistency play in improving user experience in interface design?
1.2.4.10.1. .
1.3. Using design rules
1.3.1. Applying established guidelines or principles to create effective and user-friendly interfaces.
1.3.2. Standards
1.3.2.1. set by national or international bodies to ensure compliance by a large community of designers standards require sound underlying theory and slowly changing technology
1.3.2.2. hardware standards more common than software high authority and low level of detail
1.3.2.3. ISO 9241 defines usability as effectiveness, efficiency and satisfaction with which users accomplish tasks
1.3.3. Guidelines
1.3.3.1. more suggestive and general
1.3.3.2. many textbooks and reports full of guidelines
1.3.3.3. abstract guidelines (principles) applicable during early life cycle activities
1.3.3.4. detailed guidelines (style guides) applicable during later life cycle activities applicable during later life cycle activities
1.3.3.5. understanding justification for guidelines aids in resolving conflicts
1.4. Golden rules and heuristics
1.4.1. “Broad brush” design rules
1.4.2. Useful check list for good design
1.4.3. Better design using these than using nothing!
1.4.4. Different collections e.g.
1.4.4.1. Nielsen’s 10 Heuristics (see Chapter 9)
1.4.4.2. Shneiderman’s 8 Golden Rules
1.4.4.2.1. 1. Strive for consistency 2. Enable frequent users to use shortcuts 3. Offer informative feedback 4. Design dialogs to yield closure 5. Offer error prevention and simple error handling 6. Permit easy reversal of actions 7. Support internal locus of control 8. Reduce short-term memory load
1.4.4.3. Norman’s 7 Principles
1.4.4.3.1. 1. Use both knowledge in the world and knowledge in the head. 2. Simplify the structure of tasks. 3. Make things visible: bridge the gulfs of Execution and Evaluation. 4. Get the mappings right. 5. Exploit the power of constraints, both natural and artificial. 6. Design for error. 7. When all else fails, standardize.
1.5. HCI design patterns
1.5.1. One way to approach design is to learn from examples that have proven to be successful in the past:
1.5.2. To reuse the knowledge of what made a system – or paradigm – successful.
1.5.3. Patterns are an approach to capturing and reusing this knowledge – of abstracting the essential details of successful design so that these can be applied again and again in new situations.
1.5.4. Characteristics of patterns
1.5.4.1. - capture design practice not theory - capture the essential common properties of good examples of design - represent design knowledge at varying levels: social, organisational, conceptual, detailed - embody values and can express what is humane in interface design - are intuitive and readable and can therefore be used for communication between all stakeholders - a pattern language should be generative and assist in the development of complete designs.
1.6. Questions
1.6.1. 1. How do design standarts work across systems and applications?
1.6.1.1. .
1.6.2. 2. How are the underlying theories for software design standards and hardware design standards different than each other?
1.6.2.1. .
1.6.3. 3. Why are software design standards more flexible compared to hardware design standards?
1.6.3.1. .
1.6.4. 4. How do standards differ from guidelines in interface design?
1.6.4.1. Standards are formal, authoritative rules set by organizations to ensure compliance and consistency across a large community. Guidelines, on the other hand, provide contextual advice specific to certain design situations, and they are less rigid than standards but still offer useful direction for detailed design.
2. CHAPTER-9 Evaluation Techniques
2.1. Evaluation
2.1.1. What is evaluation?
2.1.1.1. tests usability and functionality of system
2.1.1.2. occurs in laboratory, field and/or in collaboration with users
2.1.1.3. evaluates both design and implementation
2.1.1.4. should be considered at all stages in the design life cycle
2.1.2. Goals of evaluations
2.1.2.1. assess extent of system functionality
2.1.2.2. assess effect of interface on user
2.1.2.3. identify specific problems
2.1.3. Questions
2.1.3.1. 1. What are the main goals of evaluation in HCI?
2.1.3.1.1. The main goals are to assess the system's usability, measure its effectiveness, and determine how well it meets user needs.
2.2. Evaluation Design
2.2.1. Cognitive Walkthrough
2.2.1.1. Proposed by Polson et al.
2.2.1.1.1. evaluates design on how well it supports user in learning task
2.2.1.1.2. usually performed by expert in cognitive psychology
2.2.1.1.3. expert ‘walks though’ design to identify potential problems using
2.2.1.1.4. psychological principles forms used to guide analysis
2.2.1.2. For each task walkthrough considers
2.2.1.2.1. what impact will interaction have on user?
2.2.1.2.2. what cognitive processes are required?
2.2.1.2.3. what learning problems may occur?
2.2.1.3. Analysis focuses on goals and knowledge: does the design lead the user to generate the correct goals?
2.2.2. Heuristic Evaluation
2.2.2.1. Proposed by Nielsen and Molich.
2.2.2.2. usability criteria (heuristics) are identified
2.2.2.3. design examined by experts to see if these are violated
2.2.2.4. Example heuristics
2.2.2.4.1. system behaviour is predictable
2.2.2.4.2. system behaviour is consistent
2.2.2.4.3. feedback is provided
2.2.2.5. Heuristic evaluation `debugs' design
2.2.3. Review-based evaluation
2.2.3.1. Results from the literature used to support or refute parts of design.
2.2.3.2. Care needed to ensure results are transferable to new design.
2.2.3.3. Model-based evaluation
2.2.3.4. Cognitive models used to filter design options
2.2.3.4.1. e.g. GOMS prediction of user performance.
2.2.3.5. Design rationale can also provide useful evaluation information
2.2.4. Questions
2.2.4.1. 1. Explain the role of cognitive walkthroughs in identifying potential usability problems.
2.2.4.1.1. Cognitive walkthroughs are valuable for pinpointing usability issues by analyzing how effectively users can achieve their goals within an interface. By simulating user interactions and focusing on task completion, they provide insights that inform design improvements and enhance overall user experience.
2.2.4.1.2. Role of Cognitive Walkthroughs:
2.3. Evaluating Through User Participation
2.3.1. Laboratory studies
2.3.1.1. Advantages:
2.3.1.1.1. specialist equipment available uninterrupted environment
2.3.1.2. Disadvantages:
2.3.1.2.1. lack of context difficult to observe several users cooperating
2.3.1.3. Appropriate
2.3.1.3.1. if system location is dangerous or impractical for constrained single user systems to allow controlled manipulation of use
2.3.2. Fiels studies
2.3.2.1. Advantages:
2.3.2.1.1. natural environment
2.3.2.1.2. context retained (though observation may alter it)
2.3.2.1.3. longitudinal studies possible
2.3.2.2. Disadvantages:
2.3.2.2.1. distractions
2.3.2.2.2. noise
2.3.2.3. Appropriate
2.3.2.3.1. where context is crucial for longitudinal studies
2.3.3. Questions
2.3.3.1. 1. What is the difference between expert evaluation and user participation in evaluating systems?
2.3.3.1.1. Expert evaluation involves specialists analyzing the system, while user participation involves real users testing the system and providing feedback based on their experience.
2.4. Evaluating Implementations (Requires an artefact: simulation, prototype, full implementation)
2.4.1. Experimental evaluation
2.4.1.1. controlled evaluation of specific aspects of interactive behaviour
2.4.1.2. evaluator chooses hypothesis to be tested
2.4.1.3. a number of experimental conditions are considered which differ only in the value of some controlled variable.
2.4.1.4. changes in behavioural measure are attributed to different conditions
2.4.2. Experimental factors
2.4.2.1. Subjects
2.4.2.1.1. who – representative, sufficient sample
2.4.2.2. Variables
2.4.2.2.1. things to modify and measure
2.4.2.3. Hypothesis
2.4.2.3.1. what you’d like to show
2.4.2.4. Experimental design
2.4.2.4.1. how you are going to do it
2.4.3. Variables
2.4.3.1. independent variable (IV)
2.4.3.1.1. characteristic changed to produce different conditions
2.4.3.1.2. e.g. interface style, number of menu items
2.4.3.2. dependent variable (DV)
2.4.3.2.1. characteristics measured in the experiment
2.4.3.2.2. e.g. time taken, number of errors.
2.4.3.3. hypothesis
2.4.3.3.1. prediction of outcome
2.4.3.3.2. null hypothesis:
2.4.4. Experimental design
2.4.4.1. within groups design
2.4.4.1.1. transfer of learning possible
2.4.4.1.2. each subject performs experiment under each condition.
2.4.4.1.3. less costly and less likely to suffer from user variation.
2.4.4.2. between groups design
2.4.4.2.1. more users required
2.4.4.2.2. each subject performs under only one condition
2.4.4.2.3. no transfer of learning
2.4.4.2.4. variation can bias results.
2.4.5. Analysis of data
2.4.5.1. Before you start to do any statistics:
2.4.5.1.1. save original data
2.4.5.1.2. look at data
2.4.5.2. Choice of statistical technique depends on
2.4.5.2.1. type of data
2.4.5.2.2. information required
2.4.5.3. Type of data
2.4.5.3.1. discrete - finite number of values
2.4.5.3.2. continuous - any value
2.4.5.4. Analysis - types of test
2.4.5.4.1. parametric
2.4.5.4.2. non-parametric
2.4.5.4.3. contingency table
2.4.5.4.4. What information is required?
2.4.5.4.5. Parametric and non-parametric tests mainly address first of these
2.4.5.5. What information is required?
2.4.5.5.1. is there a difference?
2.4.5.5.2. how big is the difference?
2.4.5.5.3. how accurate is the estimate?
2.4.5.6. Parametric and non-parametric tests mainly address first of these
2.4.5.7. Experimental studies on groups
2.4.5.7.1. More difficult than single-user experiments
2.4.5.7.2. Problems with:
2.4.5.7.3. Subject groups
2.4.5.7.4. The task
2.4.5.7.5. Data gathering
2.4.5.8. Analysis
2.4.5.8.1. N.B. vast variation between groups
2.4.5.8.2. solutions:
2.4.5.8.3. look at interactions between group and media
2.4.5.8.4. controlled experiments may `waste' resources!
2.4.5.9. Field studies
2.4.5.9.1. Experiments dominated by group formation
2.4.5.9.2. Field studies more realistic:
2.4.5.9.3. Contrast:
2.4.6. Questions
2.4.6.1. 1) How does remote user testing differ from traditional in-person testing, and what are its advantages?
2.4.6.1.1. 1) Remote user testing allows users to participate from their own environment, providing more natural feedback. It also reduces logistical challenges and costs compared to in-person testing.
2.4.6.2. 2) What are the ethical considerations when conducting user testing in HCI?
2.4.6.2.1. 2) Ethical considerations include ensuring user privacy, obtaining informed consent, and making sure participants are not harmed or stressed during the testing process.
2.4.6.3. 3) How do usability testing methods help in the design process of interactive systems?
2.4.6.4. • What is the purpose of heuristic evaluation, and how does it differ from user testing?
2.4.6.4.1. Heuristic Evaluation is a usability inspection method where experts assess an interface against established usability principles (heuristics) to identify potential usability issues.
2.4.6.4.2. Purpose of heuristic evaluation
2.4.6.4.3. Differences from User Testing:
2.4.6.5. • Why is iterative evaluation important for the success of interactive system design?
2.5. Observational Methods
2.5.1. Think Aloud
2.5.1.1. user observed performing task
2.5.1.2. user asked to describe what he is doing and why, what he thinks is happening etc.
2.5.1.3. Advantages
2.5.1.3.1. simplicity - requires little expertise
2.5.1.3.2. can provide useful insight
2.5.1.3.3. can show how system is actually use
2.5.1.4. Disadvantages
2.5.1.4.1. subjective
2.5.1.4.2. selective
2.5.1.4.3. act of describing may alter task performance
2.5.2. Cooperative evaluation
2.5.2.1. variation on think aloud
2.5.2.2. user collaborates in evaluation
2.5.2.3. both user and evaluator can ask each other questions throughout
2.5.2.4. Additional advantages
2.5.2.4.1. less constrained and easier to use
2.5.2.4.2. user is encouraged to criticize system
2.5.2.4.3. clarification possible
2.5.3. Protocol analysis
2.5.3.1. paper and pencil – cheap, limited to writing speed
2.5.3.2. audio – good for think aloud, difficult to match with other protocols
2.5.3.3. video – accurate and realistic, needs special equipment, obtrusive
2.5.3.4. computer logging – automatic and unobtrusive, large amounts of data difficult to analyze
2.5.3.5. user notebooks – coarse and subjective, useful insights, good for longitudinal studies
2.5.3.6. Mixed use in practice.
2.5.3.7. audio/video transcription difficult and requires skill.
2.5.3.8. Some automatic support tools available
2.5.4. Automated analysis
2.5.4.1. Workplace project
2.5.4.2. Post task walkthrough
2.5.4.2.1. user reacts on action after the event
2.5.4.2.2. used to fill in intention
2.5.4.3. Advantages
2.5.4.3.1. analyst has time to focus on relevant incidents
2.5.4.3.2. avoid excessive interruption of task
2.5.4.4. Disadvantages
2.5.4.4.1. lack of freshness
2.5.4.4.2. may be post-hoc interpretation of events
2.5.5. Post-task walkthroughs
2.5.5.1. transcript played back to participant for comment
2.5.5.1.1. delayed -- evaluator has time to identify questions
2.5.5.1.2. immediately -- fresh in mind
2.5.5.2. useful to identify reasons for actions and alternatives considered
2.5.5.3. necessary in cases where think aloud is not possible
2.6. Query Techniques
2.6.1. Interviews
2.6.1.1. analyst questions user on one-to -one basis usually based on prepared questions
2.6.1.2. informal, subjective and relatively cheap
2.6.1.3. Advantages
2.6.1.3.1. can be varied to suit context
2.6.1.3.2. issues can be explored more fully
2.6.1.3.3. can elicit user views and identify unanticipated problems
2.6.1.4. Disadvantages
2.6.1.4.1. very subjective
2.6.1.4.2. time consuming
2.6.2. Questionnaires
2.6.2.1. Set of fixed questions given to users
2.6.2.2. Advantages
2.6.2.2.1. quick and reaches large user group
2.6.2.2.2. can be analyzed more rigorously
2.6.2.3. Disadvantages
2.6.2.3.1. less flexible
2.6.2.3.2. less probing
2.6.2.4. Need careful design
2.6.2.4.1. what information is required?
2.6.2.4.2. how are answers to be analyzed?
2.6.2.5. Styles of question
2.6.2.5.1. ranked
2.6.2.5.2. general
2.6.2.5.3. open-ended
2.6.2.5.4. scalar
2.6.2.5.5. multi-choice
2.7. Physiological methods
2.7.1. Eye tracking
2.7.1.1. head or desk mounted equipment tracks the position of the eye
2.7.1.2. eye movement reflects the amount of cognitive processing a display requires
2.7.1.3. measurements include
2.7.1.3.1. fixations: eye maintains stable position. Number and duration indicate level of difficulty with display
2.7.1.3.2. saccades: rapid eye movement from one point of interest to another
2.7.1.3.3. scan paths: moving straight to a target with a short fixation at the target is optimal
2.7.2. Physiological measurement
2.7.2.1. emotional response linked to physical changes
2.7.2.2. these may help determine a user’s reaction to an interface
2.7.2.3. measurements include:
2.7.2.3.1. electrical activity in brain: electroencephalogram (EEG)
2.7.2.3.2. heart activity, including blood pressure, volume and pulse.
2.7.2.3.3. activity of sweat glands: Galvanic Skin Response (GSR)
2.7.2.3.4. electrical activity in muscle: electromyogram (EMG)
2.7.2.4. some difficulty in interpreting these physiological responses - more research needed