Jan 13, 2011 IAT 334 1

IAT 334Interface Design

Task Analysis______________________________________________________________________________________

SCHOOL OF INTERACTIVE ARTS + TECHNOLOGY [SIAT] | WWW.SIAT.SFU.CA

Jan 13, 2011 IAT 334 2

Agenda

g Task Analysis g Evaluationg Predictive evaluation

– Heuristic evaluation– Discount usability testing– Cognitive walkthrough

Jan 13, 2011 IAT 334 3

Task Conformance

g Task coverage– Can system do all tasks of interest?

g Task adequacy– Can user do tasks?– Does system match real-world tasks?

Jan 13, 2011 IAT 334 4

Task Analysis

g Analyzing how people do their jobs– Go to their environment– Learn about, analyze and describe their

tasks

g Examine users’ tasks to better understand what they need from interface and how they will use it

Task Analysis

g Gather data about what users need to do or accomplish

…then…

g Represent data for interpretation and use in design decisions

Jan 13, 2011 IAT 334 5

Information to be Gathered

g Information about usersg Description of environment

– where the tasks will be performedg Major goals of the job

– what will result in a successful end state?

g User preferences & needs– before they even start: coffee, pen,

notebook, log sheets…Jan 13, 2011 IAT 334 6

Jan 13, 2011 IAT 334 7

Task Analysis

g Broad Focusg Observe users of current system(s)g Generate requirements

– Hierarchical task analysis– Knowledge-based task analysis– Entity-Relationship model

Data Gathering Techniques

1. Observation2. Interviews & Contextual Inquiry3. Ethnographyalso…4. Surveys & Questionnaires5. Focus Groups & Expert Debriefing6. Competitive Product Review7. Documentation mining8. Data logging

Jan 13, 2011 IAT 334 8

Information to be Gatheredg Tasks & Subtasks:

– Physical– Cognitive– Communication

g Conditions under which these tasks are done

g Results/outcomes of tasksg Requirements to perform task:

– Information– Communication with others– EquipmentJan 13, 2011 IAT 334 9

1. Observation

g Watch users do what they do– Typically from a distance

g Record with videotape– May require coding video later

g Take lots of notes, sketchesg Focus on specific task-relevant

behaviors in notes, but later convert to abstract subtasks

Jan 13, 2011 IAT 334 10

2. Interviews

g Engage the user more than just watching

g Structured interviews– Efficient, but requires training

g Unstructured– Inefficient, but requires no training

g Semi-structured– Good balance– Often appropriateJan 13, 2011 IAT 334 11

Semi-Structured Interviews

g Predetermine data of interestg Plan for effective question types

– How do you perform task x?– Why do you perform task x?– What information do you need to…?– Who do you need to communicate with to…?– What do you use to…?– What happens after you…?– What is the result or consequence of NOT…?

Jan 13, 2011 IAT 334 12

3. Ethnography

g Deeply contextual inquiry– “Wallow in the data”

g “Live among” the usersg Understanding the full complexity of

behavior, in its complete social context

g Note: Techniques based in sociology and anthropology--the study of humans

Jan 13, 2011 IAT 334 13

Comment

g Techniques 1-3 are similar, but differ in how “plugged in” or engaged the observer gets

g There are Pros and Cons of all these techniques

Jan 13, 2011 IAT 334 14

More!

g Often used in addition:4. Surveys & Questionnaires5. Focus Groups & Expert Debriefing6. Competitive Product Review7. Documentation mining8. Data logging

Jan 13, 2011 IAT 334 15

Jan 13, 2011 IAT 334 16

Existing System

g Usually task analysis involves an examination of an existing system, process or practice

g Watch what they do and how they do it

4. Surveys & Questionnaires

g Subjective answers in a quantitative format – What does this mean?

g Questions:– Exploratory vs. confirmatory– Open-ended vs. categorical (exhaustive)

– NB: If you ask it, use it. If you won’t/can’t use it, don’t ask it.

Jan 13, 2011 IAT 334 17

Questionnaires

g Likert scale common

Jan 13, 2011 IAT 334 18

Evaluation Questionnaire

Please complete the following questionnaire by indicating how strongly you agree or disagree with the following statements. Your responses will be kept confidential and will be used only for improving the interface that you worked with in this experiment. 1. I felt that the computer agent’s help was worthwhile. 1-----2------3------4------5------6------7

Strongly Strongly Disagree Agree

2. I found the computer agent to be intrusive. 1-----2------3------4------5------6------7 Strongly Strongly Disagree Agree

3. I found the computer agent's help to be distracting. 1-----2------3------4------5------6------7 Strongly Strongly Disagree Agree

Typical Questions

g Rank the importance of each of these tasks (give a list of tasks)

g List the four most important tasks that you perform (this is an open question)

g List the pieces of information you need to have before making a decision about X, in order of importance

g Are there any other points you would like to make? (open-ended opinion question; good way to end)

Jan 13, 2011 IAT 334 19

5. Focus Groups

g Structured Interview with groups of individuals– 3 to 10 persons– Use several different groups with different

roles or perspectives– Manage the interaction

• Avoid few people dominating the discussion

g Focus on preferences and views, not performance

g Relatively low cost, quick way to learn a lot

g Audio or video record, with permissionJan 13, 2011 IAT 334 20

6. Competitive Products

g Looking for both good and bad ideas– Functionality– UI style

g Why are they successful or unsuccessful?

g What does successful really mean?– (Note: Successful does not equal

usable)

Jan 13, 2011 IAT 334 21

7. Document Mining

g Documentation– Often contains description of how the

tasks should be done– Standards docs– Manuals– Histories– Best Practices

Jan 13, 2011 IAT 334 22

8. Data Logging

g Automatically tracking:– Keystroke/mouse clicks– Timers– Logs of transactions– Physical location/movement trackers

• Cell phones• GPS

Jan 13, 2011 IAT 334 23

Jan 13, 2011 IAT 334 24

No Existing System

g Gather documents, talk with knowledgeable people, etc.

g Can still be useful to help generate requirements

Jan 13, 2011 IAT 334 25

Task Analysis Focus

g Not on internal cognitive state of user (more on that in the near future)

g Focus on observable behaviors– Observe users, what they do, and how

they do it– What are the practices, methods, steps,

objects, …, used?

Now that you have observed…

g You have piles of notes, hours of video, surveys up to here…

g How can you digest and represent the data, to turn it into information?

Jan 13, 2011 IAT 334 26

Describe Tasks

1. Task Outlines2. Narratives3. Hierarchies & Network Diagrams

– Hierarchical Task Analysis (HTA)– Entity-Relationship Diagrams

4. Flow Charts5. Card Sorting

Jan 13, 2011 IAT 334 27

1. Task Outline

Using a lawnmower to cut grassStep 1. Examine lawn

a. Make sure grass is dryb. Look for objects laying in the grass

Step 2. Inspect lawnmowerc. Check components for tightness

1) Check that grass bag handle is securely fastened to the grass bag support

2) Make sure grass bag connector is securely fastened to bag adaptor3) Make sure that deck cover is in place4) Check for any loose parts (such as oil caps)5) Check to make sure blade is attached securely

d. Check engine oil level1) Remove oil fill cap and dipstick2) Wipe dipstick3) Replace dipstick completely in lawnmower4) Remove dipstick5) Check that oil is past the level line on dipstick

Jan 13, 2011 IAT 334 28

2. Narratives

g Describe tasks in sentencesg Often expanded version of task

outlineg More effective for communicating

general idea of taskg Not effective for detailsg Not effective for branching tasksg Not effective for parallel tasksJan 13, 2011 IAT 334 29

3. Hierarchies & Networks

g Hierarchical Task Analysis (HTA)– Graphical notation & decomposition of tasks– Tasks as sets of actions– Tasks organized into plans (describes

sequence)g Network / Entity-Relationship Diagrams

– Objects/people with links to related objects– Links described functionally and in terms of

strength

Jan 13, 2011 IAT 334 30

Jan 13, 2011 IAT 334 31

Jan 13, 2011 IAT 334 32

Hierarchical Task Decompositiong Decompose task into

– Subtasks• Multiple levels

– Plans describing ordering and conditions

Jan 13, 2011 IAT 334 33

Common Plans

g Fixed sequenceg Optional tasksg Waiting for eventsg Cyclesg Time-sharing -- parallelg Discretionary

Jan 13, 2011 IAT 334 34

Entity-Relationship

g Object-based methodology, with a real stress on relationship between objects and actions

g Involves– Concrete objects– Actors– Composite objects

Jan 13, 2011 IAT 334 35

Example

g Task: Develop design for final project– Objects - Pens, paper, drawing tools,

etc.– Actors - Mary, Bob, Sally– Composite objects - The “team”

4. Flow Charts

g Flow Chart of Task Steps– Combines Entity-relationship (network)

with sequential flow, branching, parallel tasks.

– Includes actions, decisions, logic, by all elements of the system

– Abstracted– Mature, well-known, good tools

Jan 13, 2011 IAT 334 36

Jan 13, 2011 IAT 334 37

5. Knowledge-based Analysis

g List all objects and actions involved in a task, then build a taxonomy of them

g Often times, work with domain expert to get help

Jan 13, 2011 IAT 334 38

Methodology

g Sample: – Get 3x5 cards– Put different object/action on each– Don’t worry about repetition at this

point!– Group into piles, subpiles, etc.

Jan 13, 2011 IAT 334 39

Utility

g This type of task analysis can be very useful when you’re writing a manual or some documentation– Taxonomy --- Document sections

Jan 13, 2011 IAT 334 40

Methodology

g Often list attributes, actions of objectsObject: pen simple

Attribute: color: red writing: on/off

Object: Mary actor Actions: M1: make a sketch M2: organize meeting

Jan 13, 2011 IAT 334 41

Use

g Produce documentation– Training, manuals, tutorials

g Requirements capture and system design– Helps you define requirements

document– Helps decide what should be included

g Helps interface design– Hierarchical breakdown might feed

menu design

Summary:Data Gathering Techniques

1. Observation2. Interviews & Contextual Inquiry3. Ethnographyalso…4. Surveys & Questionnaires5. Focus Groups & Expert Debriefing6. Competitive Product Review7. Documentation mining8. Data logging

Jan 13, 2011 IAT 334 42

Summary:Describe Tasks

1. Task Outlines2. Narratives3. Hierarchies & Network Diagrams

– Hierarchical Task Analysis (HTA)– Entity-Relationship Diagrams

4. Flow Charts5. Card Sorting

Jan 13, 2011 IAT 334 43