Interaction Design Course SummaryThe following sections are covered in the Interaction Design book – the sections in blue are examinable for 2011, the sections in pink are not examinable.

 

A brief example of questions to be expected in the Exam

Below are some example questions extracted from previous exam papers and assignments…. I have outlined just the basic section headers, you will need to be able to expand on these…

Define Interaction Design (Chapter 1)

Interactive Design is the process of designing interactive products to support the way people communicate and interact in their everyday working lives.

Consider your personal cell phone and choose four of Preece et al’s user experience goals – for each of the four goals describe how that usability goal is implemented in the cell phone or not

There are several usability goals including…

1. Effective 2. Efficient 3. Safe to use 4. Easy to Learn

Define an interface metaphor and state its purpose (Chapter 2)

An interface metaphor provides a structure that is similar in some way to aspects of a familiar entity but that also has its own behaviours and properties. It purpose is to help the user get the essence of the process of finding relevant information, enabling the user to link these to less familiar aspects of the functionality provided.

Give two examples of metaphors or analogies used in interaction design and explain how they are used (Chapter 2)

1. Desktop Metaphor with computers – used to describe a place where you organize everything and have things readily accessible

2. Browsing Metaphor with the internet – the idea of following links in a page through exploring what is there similar to window shopping

Explain three disadvantages of or objections to interface metaphors (Chapter 2)

1. Too constraining – the metaphor could constrain design 2. Not being able to understand the system functionality beyond

the metaphor 3. Overly literal translations of existing bad designs (e.g. computer

calculator)

Discuss interviews as a method of data gathering, referring specifically to different types of interviews and advantages of using interviews

Unstructured Interviews Semi-structured interviews Structured Interviews Focus Groups

List the four basic activities of the process of interaction design – briefly explain what each one involves (Chapter 1)

1. Identifying Needs and establishing requirements 2. Developing alternative designs that meet those requirements 3. Building interactive versions of the the designs so that they can

be communicated and assessed 4. Evaluating what is being built throughout the process and the

user experience it offers

Briefly compare the three evaluation approaches discussed in chapter 12 by identifying the strengths and weaknesses of each approach (Chapter 12 - see pg. 592)

Usability Testing – closed controlled environment Field Studies – examine what the user does in a natural

environment Analytical Evaluation – Apply heuristics, cognitive walkthroughs

& models

What are the steps involved in cognitive walkthrough? (Chapter 15)

Identify user characteristics and sample tasks Evaluators walk through the action sequences for each task with

a focus on the action, visibility of action and response of actions Record critical information including assumptions, side issues Revise design and fix the problems presented

Briefly describe each of the four interaction types and give one example of how each interaction type is represented in your cell phone (See Chapter 2)

1. Instructing – i.e. phoning a number2. Conversing – i.e. menu driven phone systems3. Manipulating – i.e. physical objects with rfid’s that a computer

monitors the manipulation of4. Exploring – cell phone games like the SIMS

Explain the difference between usability goals and user experience goals (See Chapter 1)

Usability goals include effectiveness, efficiency, safety, utility, learnability & memorability

User experience goals include satisfying, enjoyable, engaging, pleasurable, exciting & entertaining.

What according to the ISO92412 standard are the four principles of human centred design? (See Chapter 9)

1. Active involvement of users and clear understanding of user and task requirements

2. An appropriate allocation of function between users and technology

3. The iteration of design solutions4. Multi-disciplinary design

What is a scenario and how can it be used in requirements elicitation? (See Chapter 10)

A scenario is an informal narrative description that allows exploration and discussion of contexts, needs, and requirements emphasizing the context

What are the three steps of heuristic evaluation? (See Chapter 15)

1. Briefing session 2. Evaluation period 3. Debriefing session

Describe three ways in which users can be involved in the interaction design process (Chapter 9 See pages 419 - 428)

Users may be co-opted to the design team so that they are major contributors

Users may be kept informed through regular newsletters or other channels of communication

Users may be brought in during the evaluation stage in usability studies

Define and explain the core threads of the Technology as Experience Framework Model and apply these concepts to using your cell phone, giving examples.

Four core threads that make up our holistic experiences in technology as experience framework model…

1. The sensual thread – how absorbed we get while using the device, i.e. computer game that we find addictive

2. The emotional thread – does it invoke emotions such as happiness, sadness, etc

3. The compositional thread – does it have a narrative path, well thought out path

4. The spatio-temporal thread – how does it effect our space and time

What is meant by the term heuristic?

A heuristic is a experience-based technique for problem solving, learning, and discovery. Heuristic methods are used to speed up

the process of finding a satisfactory solution, where an exhaustive search is impractical.

List four heuristics that are suitable for evaluating a cell phone SMS sending task

1. Visibility of system status 2. User control and freedom 3. Error prevention 4. Aesthetic and minimalistic design

Apply the four basic activities of interaction design from chapter 9 to the possible redesign of the myUnisa Website

1. Identifying needs and establishing requirements for the user experience

2. Developing alternative designs that meet those requirements 3. Building interactive versions of the designs 4. Evaluating what is being built throughout the process and the

user experience it offers

Briefly describe the four interaction types discussed in Chapter 2

1. Instructing – i.e. typing commands on a console 2. Conversing – i.e. menu driven phone systems 3. Manipulating – i.e. physical objects with rfid’s that a computer

monitors the manipulation of 4. Exploring – virtual 3d worlds i.e. sim city?

Describe four types of pleasure proposed in Patrick Jordon’s pleasure model

1. Physio-pleasure – Feels nice to touch 2. Socio-pleasure – Fun to have family participate with it together 3. Psycho-pleasure – Satisfying to use 4. Ideo-pleasure (cognitive) – Makes sense to use, i.e. Eco-friendly

car

List the four different types of requirement categories (See Chapter 10)

1. Functional Requirements 2. Non-Functional Requirements

Or it could be the following…

1. Data requirements2. Environmental requirements3. User characteristics4. Usability goals and user experience goals

What is a conceptual model?

A conceptual model is a high level description of how a system is organized and operates. An abstraction that outlines what people can do with a product and what concepts are needed to understand interacting with it.

Briefly describe four components that make up a conceptual model (See Chapter 2 page 51-52)

Major metaphors and analogies that are used to convey to the user how to understand what a product is for and how to use it for an activity

The concepts that users are exposed to through the product, including the task domain objects they create and manipulate, their attributes, and the operations that can be performed on them

The relationships between those concepts The mappings between the concepts and the user experience

the product is designed to support or invoke

Give five examples of collaborative technologies that support communication

email videoconferencing videophones computer conferencing chat rooms instant messaging

Briefly discuss three aspects of interfaces that can contribute to user frustration

Possible reasons include

Application doesn’t work properly or crashes System doesn’t do what the user want it to User’s expectations are not met System does not provide sufficient info to let user know what to

do Error message are vague, obtuse or condemning

Appearance of interface too noisy, garish, gimmicky, or patronising

System requires users to carry out many steps to perform a task only to discover a mistake was made somewhere along the line and they need to start al over again

What are the four key issues that determine the success of a data gathering exercise?

1. Setting goals 2. Relationship between data collector and provider 3. triangulation 4. pilot studies

List six ways in which data can be gathered to establish user requirements.

1. Interviews 2. Focus Groups 3. Questionnaires 4. Direct Field Observation 5. Direct Lab Observation 6. Indirect Observation

What are the steps involved in cognitive walkthrough. (See Chapter 15 page 702 & 703)

1) The characteristics of typical users are identified and documented and sample tasks are developed that focus on the aspect of the design that will be evaluated.

2) A designer or one or more evaluators come together to do the walkthrough

3) The evaluators walk through the action sequences for each task with a focus on the following..

- Will the correct action be sufficiently evident to the user - Will the user notice that the correct action is available - Will the user associate and interpret the response from the

action correctly

4) As the walkthrough is being done a record of critical information is compiled in which

- The assumptions about what would cause problems are recorded

- Notes about side issues and design changes are made - A summary of results is compiled

5) The design is then revised to fix the problem presented

INF3720 – Interaction Design Chapter 1 Summary

Aims of Chapter 1

Explain the difference between good and poor interaction design Describe what interaction design is and how it relates to human-computer

interaction and other fields Explain what is meant by the user experience and usability

Summary

Good and Poor Interaction DesignThe following examples were used to illustrate good and poor design.

1. Voicemail system2. Remote control

A key question for interaction design is how do you optimize the user’s interactions with a system, environment, or product. One way is to make choices based on an understanding of the users. This would include:

Taking into account what people are good and bad at Considering what might help people with the way they currently do things Thinking through what might provide quality user experiences Listening to what people want and getting them involved in the design Using ‘tried and tested’ user-based techniques during the design process

What is Interaction Design?Interaction design means…

Designing interactive products to support the way people communicate and interact in their everyday working lives

Interaction design uses several different components including some of the following academic disciplines…

 

It also implements the following Design Practices…

 

 

Is Interaction Design beyond HCI?

The main difference between ID and HCI is one of scope. ID has a much wider net in terms of theory, research, and practice of designing user experiences. HCI has a much narrower focus being concerned with the design, evaluation and implementation of interactive computing systems.

The process of Interaction DesignThe process involves four basic activities…

1. Identifying needs and establishing requirements for the user experience2. Developing alternative designs that meet those requirements3. Building interactive versions of the designs so that they can be

communicated and assessed4. Evaluating what is being built throughout the process and the user

experience it offers

Interaction Design and the User Experience6 Usability Goals

Effective to use (effectiveness) – how good is a product at doing what it is supposed to do

Efficient to use (efficiency) – once a user has learned how to use a product, can they sustain a high level of productivity

Safe to use (safety) – protecting a user from dangerous conditions and undesirable situations

Having good utility (utility) – Does it allow the user to carry out all their tasks in the way they would want to do them

Easy to learn (learnability) – Can the user work out how to use the product easily

Easy to remember how to use (memorability) – How easy is it for the user to remember how to use the product

Positive User Experience Goals

Satisfying Enjoyable Engaging Pleasurable Exciting Entertaining etc.

5 Design Principles

Visibility – The more visible functions are, the more likely users are to use them

Feedback – Send feedback when an action is performed Constraints – restricting the kinds of user interaction that can be

performed at a given moment – i.e. deactivating menu buttons Consistency – Interfaces that have similar operations look similar Affordance – Indicates to a user how to use the operation – i.e. a dial that

one turns to wind up a clock

INF3720 – Interaction Design Chapter 2 Summary

Aims of this chapter

Explain what is meant by the problem space Explain how to conceptualize interaction Describe what a conceptual model is and how to begin to

formulate one Discuss the pros and cons of using interface metaphors as part

of a conceptual model Outline the core interaction types for informing the development

of a conceptual model Introduce theories, models, and frameworks as a way of

informing interaction design

Summary

Understanding the problem space

Problem space - Understand and conceptualize what is currently the user experience/product and how this is going to be improved or changed.

Different people have different perspectives, defining a problem space is usually best done by a group of different individuals.

Questions to ask…

Are there problems with an existing product or user experience? Why do you think there are problems? How do you think your proposed design ideas might overcome

these? If you have not identified any problems  and instead are

designing for a new user experience how do you think your proposed design ideas support, change, or extend current ways of doing things?

Conceptualizing the design space

A conceptual model is a high level description of how a system is organized and operates.

The most important thing to design is the user’s conceptual model. Everything else should be subordinated to making that model clear, obvious, and substantial. That is almost exactly opposite to how most software is designed.

A conceptual model is an abstraction that outlines what people can do with a  product and what concepts are needed to understand how to interact with it.

Some things that a conceptual model could comprise of would include…

The major metaphors and analogies that are used to convey to the user how to understand what a product is for and how to use it for an activity.

The concepts that users are exposed to through the product, including the task domain objects they create and manipulate, their attributes, and the operations that can be performed on them.

The relationship between those concepts The mappings between the concepts and the user experience

the product is designed to support or invoke

The benefits of conceptualizing a design in general  terms early on in the design process encourages design teams to…

Orient themselves towards asking specific kinds of questions about how the conceptual model will be understood by the targeted users

Not to become narrowly focussed early on To establish a set of common terms they all understand and

agree upon, reducing the chance of misunderstandings and confusion arising later on

Interface metaphors and analogies

An interface metaphor is considered to be a central component of a conceptual model.

Interface metaphors are often composites – i.e. they combine quite different pieces of familiar knowledge with the system functionality – i.e. Desktop or Scrollbar or Toolbar

Opposition to using interface metaphors

A mistake often made is to make an interface metaphor behave/look exactly the same way as the real life object. Example of this would be implementing a computer calculator exactly the same way a real calculator is implemented – which would not make sense as the real calculator has constraints such as size and cost that a computer calculator would not have that effects the user experience (size and number of buttons).

Some reasons for opposition to using interface metaphors include…

Breaking the rules – i.e. recycle on the desktop whereas in real life it would be under the desktop

Too constraining – selecting a file form a list instead of searching for it

Conflicts with design principles Not being able to understand the system functionality beyond

the metaphor Overly literal translation of existing bad designs Limits the designers imagination in conjuring up new paradigms

and models

Interaction types

Four fundamental types of interaction someone can have with a product/system

1. Instructing – i.e. typing commands on a console2. Conversing – i.e. menu driven phone systems3. Manipulating – i.e. physical objects with rfid’s that a computer

monitors the manipulation of4. Exploring – virtual 3d worlds i.e. sim city?

There are many other ways, however the four cover the main types.

Theories, Models, and Frameworks

Theories – numerous theories have been imported into human computer interaction, providing a means of analysing and predicting the performance of systems.

Models – Models are typically abstracted from a theory coming from a contributing discipline

Frameworks – a number of frameworks have been introduced in ID to help designers constrain and scope the user experience. Frameworks have traditionally been based on theories of human behaviour, but they are increasingly being developed from the experience of actual design practice and the findings arising from user studies.

INF3720 – Interaction Design Chapter 4 Summary

Aims if this chapter

Explain what is meant by communication and collaboration Describe the social mechanisms that are used by people to communicate

and collaborate Outline the range of collaborative systems that have been developed to

support this kind of social behaviour Describe some of the new forms of social behaviour that have emerged as

a result of the proliferation of mobile devices, web-based services, and applications

Summary

Social mechanisms in communication and collaborationUnderlying the various forms of communication are mechanisms and practices that have evolved to enable us to maintain social order. Three core forms of social mechanisms that are used…

1. The use of conversational mechanisms to facilitate the flow of talk and help overcome conversational breakdowns

2. The use of coordination mechanisms to allow people to work and interact together

3. The use of awareness mechanisms to find out what is happening, what others are doing, and conversely to let others know what is happening

Three basic rules for conversational analysis…

1. The current speaker chooses the next speaker by asking an opinion, question, or request

2. Another person decides to start speaking 3. The current speaker continues talking

Kinds of Conversations

Informal Formal

Designing collaborative technologies to support conversation

A central concern is to allow people to communicate collaboratively when they are not physically co-located.

Communicating in physically different locations can be achieved with a variety of communication medium including...

Email Videoconferencing

Videophones Chat rooms Online MUDS (multi user role playing environments) MOOS (text based environments that grew out of MUDS)

Communicating in co-located settings with a  number of shareable interfaces including…

Smart boards Digital Table tops

Coordination MechanismsTo help us we use a number of coordinating mechanism including…

verbal and non-verbal communication schedules, rules, and conventions shared external representations

People adapt the social protocols used in face-to-face collaboration when using collaborative technologies

Cell phones, web based social and community services have brought about significant changes in the way people keep in touch

INF3720 – Interaction Design Chapter 5 Summary

Aims of this chapter

Explain what expressive interfaces are and the effects they can have on people

Outline the nature of user frustration and how to reduce it Describe how technologies can be designed to change people’s attitudes

and behaviour Debate the pro’s and con’s of applying anthropomorphism in interaction

design Describe the affective aspects used in interface agents and interactive

physical toys Present models and frameworks of affect that can be applied to interaction

design Enable you to critique the persuasive impact of an online agent on

customers

Summary

What are affective aspects? The main focus is on how interactive systems can be designed to provoke an emotion within the user.

Expressive interfaces and positive emotions can be used in an interface to

Convey emotional states Elicit certain kinds of emotional responses in users

One benefit of using expressive embellishments is that they provide reassuring feedback to the user that can be both informative and fun. They can also sometimes have the opposite effect.

The style of an interface in terms of the shapes, font, colours, balance, white space can also have an impact on the interfaces affectiveness.

Rule of thumb is that the better an interface is designed, the more tolerant the user will be if things do not work properly.

Frustrating Interfaces and Negative EmotionsThings that can cause frustration include

When an application doesn’t work properly or crashes When a system doesn’t do what the user wants it to do When a user’s expectations are not met When a system does not provide sufficient information to let the user

know what to do When error messages pop up that are vague or obtuse When the appearance of an interface is too noisy, garish, or patronizing When a system requires you to carry out to many steps to accomplish a

task

Often user frustration is a result of bad design, no design, inadvertent design, or ill-thought-out design.

Some things to keep in mind

Avoid gimmicks Avoid non descriptive error messages Avoid making the user wait unnecessarily Avoid complicated upgrade processes Avoid cluttered design and extreme us of graphics / colours

Anthropomorphism in Interaction DesignAnthropomorphism is the propensity people have to attribute human qualities to objects

People have a tendency of attributing human qualities to objects and animals such as pets, toys, etc This is becoming more common in interaction design.

Examples would include cuddly toys that respond to their environment, helping agents that have human like qualities, etc..

There are people who are for and against the concept. Some of the reasons for people against the concept include…

Can lead people into a false sense of belief Can be deceptive

Interface agents, virtual pets, and interactive toysExamples include Tamagutchi pets, The Woogles, etc.

A lot of work has been put into designing interactive toys etc. including…

Recognizing and responding to verbal and non-verbal input Generating verbal and non-verbal output Coping with breakdowns, turn-taking, and other conversational

mechanisms Giving signals that indicate the state of the conversations as well as

contributing new suggestions for the dialog

Models of affective aspectsEmotional design model

Pleasure Design Model

Proposes four conceptually distinct types of pleasure

Physio-pleasure – Feels nice to touch Socio-pleasure – Fun to have family participate with it together Psycho-pleasure – Satisfying to use Ideo-pleasure (cognitive) – Makes sense to use, i.e. Eco-friendly car

Technology as a Framework

Four core threads that make up our holistic experiences

1. The sensual thread – how absorbed we get while using the device, i.e. computer game that we find addictive

2. The emotional thread – does it invoke emotions such as happiness, sadness, etc

3. The compositional thread – does it have a narrative path, well thought out path

4. The spatio-temporal thread – how does it effect our space and time

These aspects are there to help designers think of the different threads and the experience they will invoke.

INF3720 – Interaction Design Chapter 7 Summary

Aims of this chapter

Discuss how to plan and run a successful data gathering program Enable you to plan and run an interview Enable you to design a simple questionnaire Enable you to plan and execute an observation

Summary

Four Key Issues

1. Setting Goals – outline what the objective of the exercise is2. The relationship with participants – get participants to give permission to

have their data used if necessary3. Triangulation – Use more than one data gathering technique to tackle a

goal4. Pilot Studies – Run a pilot study before doing the main study to iron out

bugs, do not use the same people in the pilot study in the main study as they now have an expectation

Data RecordingVarious methods and tools to use to assist in recording data including…

Notes plus camera Audio plus camera Video

Interviews

Unstructured Interviews – Open ended conversational Structured Interviews – Predetermined questions are asked with available

answers i.e. which of the following best describes… Semi-Structured Interviews – Combination of Unstructured and Semi-

Structured Focus Groups – Facilitator with group members

Planning and conducting an interview

Involves developing the set of questions or topics to be covered. Developing interview questions requires determining if the questions will be open or closed. The following are suggestions…

Compound sentences can be confusing, so split them into two separate questions

Interviewers may not understand jargon or complex language Try and keep questions neutral

Running an interview

Have an introduction – interviewer introduces himself Warm-up session – easy non-threatening questions Main session – questions presented in logical order Cool off period – few easy questions Closing session – end the interview

QuestionnairesDesigning questionnaires with structure include…

Think about ordering of questions. Impact can be effected by order Consider whether you need different versions of questionnaires for

different populations Provide clear instructions on how to complete the questionnaire Find a balance between keeping whitespace and the questionnaire

compact

Question and response format…

Checkboxes and ranges Rating scales

Administering questionnaires…

2 Important issues when administering questionnaires…

1. Make sure you reach a representative sample of the audience2. Make sure you get a reasonable response rate

ObservationDirect observation in the field

Structuring frameworks for observation in the field

The person The place The thing

Degree of Participation

Depends on the type of study. You can get different types of observers including

Passive Observer – does not take part, merely observers Participant Observer – participates and interacts with those being

observed

Ethnography

Is a qualitative method aimed to learn and understand cultural phenomena which reflect the knowledge and system of meanings guiding the life of a cultural group.

See wiki for more info

Choosing and combining techniquesDirect observation in controlled environments

This usually occurs in a usability laboratory. Same basic data recording techniques are used.

The think aloud technique

In a controlled environment the interviewer can afford to be more intrusive. One way is to say what they are thinking as it is happening.

Indirect observation

Diaries Interaction Logs

INF3720 – Interaction Design Chapter 9 Summary

Aims of this Chapter

Consider what doing interaction design involves Explain some advantages of involving users in development Explain the main principles of a user-centred approach Ask and provide answers for some important questions about

the interaction design process Introduce the idea of a lifecycle model to represent a set of

activities and how they are related Describe some lifecycle models from software engineering and

HCI and discuss how they relate to the process of ID Present a lifecycle model of interaction design

Summary

What is involved in interaction design

Design involves working on requirements, designing a solution, producing the solution and evaluating it.

Design is about trade offs – cost vs. effectiveness etc. and so key to design is generating alternatives.

Involving users and others in design process means that the designs and potential solutions need to be communicated to people other than the original designer. There are many ways of doing this.

The importance of involving users

The best way to make sure that development continues to take users activities into account is to involve real users throughout the development. In this way developers can better understand user goals leading to a more appropriate more usable product. It also assists in setting expectations of the user.

Expectation management is the process of making sure that the users view and expectations of the new product are realistic.

It is better to exceed user expectations than to fall below them.

There are several ways to set user expectations including

Involving them throughout the design and developing stages Have timely training

Degrees of user involvement

User involvement depends on what is involved and the nature of the product, on one end of the scale you can have the user involved all the time on the other end of the scale you could keep them informed via newsletters

How actively users should be involved is a matter of debate, too much user involvement can lead to issues and not enough user involvement can lead to poor solutions.

What is a user centred approach

Three principles that lead to a user centred approach

Early focus on users and tasks – see goals below Empirical measurement – be able to measure what you are

wanting to achieve Iterative design – perform design in small steps

With an early focus on users and tasks it can be further broken down into categories

User tasks and goals are the driving force behind the development

User’s behaviour and context of use are studied and the system is designed to support them

User characteristics are captured and designed for Users are consulted throughout development from earliest

phases to the latest and their input is seriously taken into account

All design decisions are taken within the context of the users, their work, and their environment

Four Basic activities of Interaction Design

1. Identifying needs and establishing requirements for the user experience

2. Developing alternative designs that meet those requirements3. Building interactive versions of the designs4. Evaluating what is being built throughout the process and the

user experience it offers

Some practical issues that need to be considered

Who are users? What do we mean by needs? How do you generate alternative designs? How do you choose among alternatives?

Lifecycle models: showing how the activities are related

Some software engineering lifecycle models

The waterfall lifecycle model The spiral lifecycle model Rapid applications Development Agile development

Lifecycle models in HCI

The star lifecycle model The usability engineering lifecycle Human centred design process for interactive systems

Star Lifecycle Model

 

 

Does not specify any ordering of activities Activities are highly interconnected Evaluation is central to this model – whenever an activity is

complete it must be evaluated

Usability Engineering Lifecycle

Essentially has 3 tasks

1. Requirements Analysis2. Design / Testing / Development3. Installation

ISO 13407 Human-centred design processes for interactive systems

International standard for providing guidance on human centred design activities.

Standard identifies four principles of human centred design

1. Active involvement of users and clear understanding of user and task requirements

2. An appropriate allocation of function between users and technology

3. The iteration of design solutions4. Multi-disciplinary design

It specifies four human-centred design activities as being central to a system development project:

1. To understand and specify the context of use2. To specify the user and organizational requirements3. To produce design solutions4. To evaluate designs against requirements

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INF3720 – Interaction Design Chapter 10 Summary

Aims of this chapter

Describe different kinds of requirements Enable you to identify examples of different kinds of

requirements from a simple description Explain how different data gathering techniques may be used

during the requirements activity Enable you to develop a scenario, a use case, and an essential

use case from a simple description Enable you to perform hierarchical task analysis on a simple

description

Summary

What, How and Why

The process works in a cycle..

Why bother? The importance of getting it right…

A large number of IT projects fail due to bad implementations or incorrect specifications.

It is cheaper to analyse than to develop If you identify the needs initially substantial savings in costs

What are requirements?

Two types of requirements typically identified

Functional Requirements – the core problem it aims to solve. What a product should do.

Non-functional requirements – size, speed…

Other types of requirements include…

Data requirements Environmental requirements User characteristics Usability goals and user experience goals

Data gathering for requirements

The main purpose of data gathering for requirements is to collect sufficient relevant, and appropriate data so that a set of stable requirements can be produced./

3 common forms of data gathering include

1. Interviews2. Questionnaires3. Observation

Interviews include…

Structured Interviews Semi Structured Interviews Unstructured Interviews Focus Groups

Observation include…

Direct observation Indirect Observation Studying documentation Researching similar products

Contextual Inquiry

Contextual inquiry is one of seven parts of contextual design, which is a structured approach to the collection and interpretation of data from fieldwork with the intention of building a software-based product.

Contextual inquiry rests on four main principles

1. Context – go to the workplace and see what is happening2. Partnership – developer and user should collaborate in

understanding the work

3. Interpretation – observations must be interpreted in order to be used in design

4. Focus – Keep the data gathering focussed on your goals

Data gathering guidelines for requirements

Focus on identifying stakeholders needs Involve all the stakeholder groups Support the data gathering sessions with suitable props

Data analysis, interpretation, and presentation

The aim here is to structure and record descriptions of requirements.

Various methods to diagram these at different levels including class diagrams, sequence diagrams, Entity Relationship Diagrams

Task Description

Descriptions of business tasks have been used within software development for many years. There are many different flavours of task descriptions including the following…

Scenarios – informal narrative description that allows exploration and discussion of contexts, needs, and requirements emphasizing the context

Use cases – focus on user goals, but emphasis is on a user-system interaction. A use case has one or more actors, goals and normal course (outcome desirable). Generally described graphically

Essential Use Cases – represent abstractions from scenarios and tries to avoid the assumptions of a traditional use case

An essential use case is a structured narrative consisting of three parts:

1. Name that expresses the overall intention2. A stepped description of user actions3. A stepped description of system responsibility

Task Analysis

Main purpose is to investigate an existing situation, not to envision new products. Used to analyse the underlying rationale and purpose of what people are doing and what they are trying to achieve.

Hierarchical Task Analysis

Involves breaking a task down into subtasks and then into sub-subtasks. The starting point is the user goal, this is then examined and the main

tasks associated with achieving that goal are identified. Where appropriate these tasks are subdivided into subtasks

INF3720 – Interaction Design Chapter 15 Summary

Aims of this chapter

Describe the important concepts associated with inspection methods Show how heuristic evaluation can be adapted to evaluate different types

of interactive products Explain what is involved in doing heuristic evaluation and various kinds of

walkthrough Describe how to perform two types of predictive techniques, GOMS and

Fitts Law, and when to use them Discuss the advantages and disadvantages of using analytical evaluation

Summary

Inspections: Heuristic EvaluationsHeuristic evaluation is a usability technique in which experts guided by a set of usability principles known as heuristics evaluate whether user interface elements such as dialog boxes, menus, conform to the principles. Some of the usability principles included

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

Doing heuristic evaluation has three stages

1. Briefing session 2. Evaluation period 3. Debriefing session

Inspection: WalkthroughsCognitive Walkthroughs

Cognitive walkthroughs involve simulating a user’s problem-solving process at each step in the human-computer dialog.

They focus on evaluating designs for ease of learning. The steps involved in cognitive walkthroughs are…

1) The characteristics of typical users are identified and documented and sample tasks are developed that focus on the aspect of the design that will be evaluated.

2) A designer or one or more evaluators come together to do the walkthrough

3) The evaluators walk through the action sequences for each task with a focus on the following..

- Will the correct action be sufficiently evident to the user - Will the user notice that the correct action is available - Will the user associate and interpret the response from the action

correctly

4) As the walkthrough is being done a record of critical information is compiled in which

- The assumptions about what would cause problems are recorded - Notes about side issues and design changes are made - A summary of results is compiled

5) The design is then revised to fix the problem presented

Pluralistic walkthroughs

Pluralistic walkthroughs are a type of walkthrough in which users, developers and usability experts work together to step through a task scenario, discussing usability issues associated with dialog elements involved in the scenario steps. Each group of experts is asked to assume the role of a user. The walkthroughs are then done following a series of steps…

1. Scenarios are developed in the form of a series of hardcopy screens representing a single path through the interface.

2. The scenarios are presented to the panel of evaluators and the panellists are asked to write down the sequence of actions they would take to move from one screen to another. They do this individually without conferring.

3. When everyone has written down their actions, the panellists discuss the actions that they suggested for that round of review

4. Then the panel moves on to the next round of screen. This process continues until all the scenarios have been evaluated.

Some benefits include…

Strong focus on users tasks at a detailed level Lends well to participatory design practices

Limitations include…

expensive having to get a group of experts together slow rate of progress major time constraints

Predictive modelsThe GOMS model

Acronym stands for Goals, operators, methods and selection rules

Description of each section below…

Goals – particular state the user wants to achieve Operators – cognitive process and physical actions that need to be

performed in order to attain those goals Methods – learned procedures for accomplishing the goals Selection rules – determine which method to select when there is more

than one available for a given stage of a task

Benefits of GOMS

Allows comparative analyses to be performed for different interfaces, prototypes, or specifications

Limitations of GOMS

Has a highly limited scope Intended to be used only to predict expert performance does not allow for errors to be modelled can only make predictions about predictable behaviour

The keystroke level model

The keystroke level model differs from GOMS model in that it provides actual numerical predictions of user performance. Tasks can be compared in terms of the time it takes to perform them when using different strategies. The main benefit of making these kinds of quantitative predictions is that different features of systems and applications can be easily compared to see which might be the most effective performing specific kinds of tasks.

The predicted time it takes to execute a given task is calculated by describing the sequence of actions involved and then summiung together the approximate times that each one will take.

Fitt’s Law

Fitt’s law predicts the time it takes to reach a target using a pointing device. In ID it is used to describe the time it takes to point at a target based on the size of the object and the distance to the object.

In a nutshell the bigger the target the easier and quicker it is to reach it.

Fitt’s law also predicts that the most quickly accessed targets on any computer display are the four corners of the screen