External and Task Analyses · Personae •There are usually several personae •Choose one as the principle or head persona-Whose goals are the most important?-Whose goals subsume

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Nov-4-05 SMD157, External & Task Analyses 1 L

INSTITUTIONEN FÖRSYSTEMTEKNIK

LULEÅ TEKNISKA UNIVERSITET

External and Task Analyses

SMD157

Human-Computer Interaction

Fall 2005


Overview

• Traditional software development

• External analysis

• Example external analysis

• Task analysis

• Example task analysis




Traditional Software Development

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The Software Life Cycle:Six Phases

RequirementsDefinition

Specification Implementation

Testing

InstallationMaintenance


Traditional Design Methods

• Focus on the technical aspects of the system- Database used,

- Data stored,

- Computer hardware requirements, ...

• Focus on the quality requirements- Security provided,

- Relative freedom from errors,

- Commented code, ...


Traditional Development Methods

• Linear Process- Write specifications

- Build system

- Test against specifications

- Deploy

• Result ⇒ Unusable Systems

• Why?- The non-technical is very important.

- Remember the Vincennes

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External Analysis


External Analysis

• Used to collect the non-technical requirements

• Characterizes- The users

- Their work

- The work environment

• Goals- Understand external (outside the system) factors

- Identify system services

- Identify usability goals


Characterizing the User

• User characteristics- Age, Gender, Physical abilities, Education, Goals

- Cultural or ethnic background, Training, Motivation

• Usage profiles- Novice or first-time users

- Knowledgeable intermittent users

- Expert frequent users

- Division of labor

+ Different assignments or always the same?

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Creating Personae, Fictional Users

• A Fictional user is called a “Persona”- Detailed description, age, sex, education, …

- Include Goals

- Write them up!

• It is easier to design a product for someone.• Design for the user! AND, you are not the user!

⇒ Create fictional users


Personae

• There are usually several personae

• Choose one as the principle or head persona- Whose goals are the most important?

- Whose goals subsume the goals of other personae?

- Who must be satisfied for the system to succeed?

• Focus on the head persona


A Note on Goals

• User goals:- Want to escape boredom

- Don’t want to be made to feelstupid

- Don’t want to work too hard

- Want to get the job done, notfight with the computer

- Want to get done and dointeresting stuff, like ski!

• Work goals:- Want workers to accomplish

the maximum

- Want to do it cheaply

- Want workers to accomplish aset of tasks (e.g., sellinsurance)

- Hereafter, work goals will becalled tasks.

User goals and work goals are not the same.

The system cannot violate user goals andmust allow work goals to be accomplished!

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Characterizing the Work

• What is done? How?- Pay attention to exceptions and special situations!

• How does information flow?- Steps, sequences, and parallel tasks

• Is work:- Performed by a group?

- Coordinated with others?

• Current tools

• Current artifacts (reports, documents, ...)


Example, Air Traffic Control

• The British Aviation Authority decide to upgrade the airtraffic control system in the late 1980’s.

• A new system know as RD3 was developed.- Added extra display capabilities

- Enabled controllers to manage a sector by themselves

• The system was not accepted

• Why was the less technically advanced solutionpreferred?


Air Traffic Control, the Answers

• RD3 ignored current work structure:- Controllers managed a sector with the aid of assistants who:

+ Managed the information about flights on paper strips

+ Helped identify potential conflicts

- They were supervised by a chief who:

+ Supervised several sectors

+ Smoothed the handoff

+ Looked for conflicts between sectors

+ Handled unusual situations

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Air Traffic Control, the Answers

• RD3:- Had more complex displays

- Made it impossible for the chief to handle unusual situations

- Increased the responsibilities of the individual controller

- Had properties that lead to distrust


Example, a Crime Statistics Reporting System

• Was deployed in Northern England primarily to providemanagement reports about crime trends.- Used to plan manpower shifts

- Used to asses the results of these shifts

• Turned out to have an unexpected benefit- Detectives used it to help clear up crimes

- Even though the UI was awful


Environment

• Can affect system use:- Noise is unacceptable in a library

- Background noise can render speech systems useless.

- Audible warning signals can be vital in a visually crowdedenvironment

• Check- What does the work area look like?

- Are some tasks allocated special areas?

- Where are the users?

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Environment

• Other factors:- Language

- Domain concepts

- Domain objects


Environment, Example

• Underwater PC

• Problem:- Not waterproofing

- Interaction

• Why:- One hand free

- Noise disturbs voicerecognition

- Track balls require flat surface

• Solution- Cord keyboard in grip


Methods for External Analysis

• Interviews

• Passive observation

• Active participation

• Analysis of the results

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Interviews

• Prepare general questions in advance.

• Let the interviewee talk.

• Start with having them describe familiar, routine things

• Be alert for special situations.- Systems must handle exceptions

- Collections example

• Usually audio recorded, but ask when the appointmentis made.


Semi-Structured Questions

• What do you do?

• Why do you do it?

• How do you do it?

• What are the preconditions?

• What is the result?

• What errors can occur?

• How do you fix them?

• Obtains the user’s goal.• Gets the method.

• Gets subtasks, userecursively.

• Finds out the outsideinfluences.

• Examines product orpurpose.

• Capture the errors.• Capture error correction.


Things to Watch

• People will often tell you the official story.

• What users say they prefer and what they actuallyprefer when the system is implemented are oftendifferent.- Evaluation with out the experience is dubious

• People away from the work environment and the taskdon’t remember much or accurately.- Interview in the context of the task. (Contextual Inquiry)

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Passive and Active Observation

• Passive- Video observations

- Taking notes from the sidelines

- Beware of the Hawthorne effect!

• Active- Become a member of the work group

- Participate in the work while taking note.

• Participatory design


Analysis

• Create transcripts

• Assemble and collate information

• Form theories about the work

• Test them against the data


Output

• Description of personae, head persona

• Specification of system services- Broad description of what the system should do, not detailed

functions.

- Limit the system scope and the implementation problem

• Usability goals

• Scenarios- Stories of personae using the system

- Can be recorded as a UML use case or a storyboard

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Usability Goals

• Speed of performance

• Error incidence

• Ease of error recovery

• Magnitude of task to learn the system

• Ease of retention of operating knowledge

• Customizability to the user way of working

• Support for reorganization of activities

• User satisfaction


Storyboard

Example

1. Håkan works as an opti-mization expert at Ericsson.One day, he’s called to aclient’s site to s olve somecomplex problems with net-work performance. As usual,it’s a long flight to g etthere...

2. In the morning of the firstday, Håkan gets an intro-duction to the problem areasby the client’s own networkoptimizers.

3. Customer complaints tellHåkan where to look, but inorder to pinpoint the p rob-lematic cell(s), he and t heother optimizers take aTEMS, mobile test instru-ment, and drive in the area.

abbreviated




Example External Analysis

PDA Controller for Copiers

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Example

• Every teacher at LTU is to get a PDA with a wirelessconnection

• The PDA will be used operate the copy machines.Specifically:- Accounting by activity will be entered

- The copier will be programmed via the PDA instead of thecontrol panel

• Design a PDA program to accomplish the goals.


Personae

• The main persona is a teacher- Håkan

- Swedish, male, 40ish, well educated, doesn’t have time tofiddle with technology, experienced user of basic “office”programs

- Main goal is to get the teaching done, not fiddle with thecopier

• Other personae- Secretaries, administrators, copier service personal


Example, Use of the Copier(by a Teacher)

• What do you do?- Make single copies of

individual documents.

- Create two-sided copies ofone-sided documents orarticles from books.

- Make one sided copies ofarticles as masters for coursecompendiums

- Make compendiums.

• Why?- I need an extra copy.

- To read on the plane, becausethey are lighter and less bulky.

- Single sheet feed, 1-sided to 2-sided is the fastest mode toproduce the lest bulky 2-sidedcopies.

- In a hurry and can’t send it out.

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Example

• How do you do it?- From a book for compendium masters

+ Set up the copier for input from a book+ Copy each pair of pages that has at least part of the

article+ Check the copies to see that they are readable+ Throw away pages that aren’t part of the article.

- For 2-sided copies+ as above, plus+ run the one-sided pages through on 1->2 copying


Example

• Preconditions- Marking the article

- Copier free, …

• Results- A stapled copy of the article in A4 format


Example

• Errors- Forget to set staple mode

- Bad one-side copies

- Paper jam

- Missing pages from thearticle

• Corrections- Hand staple

- Redo

- Clear and redo

- Copy them and sortoutput

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One Might also AskHow Often?

• Make single copies ofindividual documents.

• Create two-sided copies ofone-sided documents orarticles from books.

• Make one sided copies ofarticles as masters for coursecompendiums

• Make compendiums.

• Often, half of the time

• Frequently

• Once or twice per term, butthere are many articles.

• Only, if I must.




Task Analysis


Task Analysis

• Organization of user interaction with the system into:- Tasks (work goals)

- Methods

• Constructs a model of user/system interaction- Usually hierarchically composed

- Usually emphasizes sequence of operation

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Task Analysis

• A description of the tasks for each class of user(personae) is required.

• How to do these tasks becomes the highest-level set ofuser tasks.

• Refine the task analysis until you have a description ofwhat each user must know to perform each task.

• You must have this information available when the userneeds it. This will influence your display designs.


Input

Typical Task

Transformation Output


Questions to AnswerAbout the Task

• Inputs- What information is needed?

- What are the characteristics ofthe information sources?(reliable?, in needed form?)

- What is the availability of theinformation?

- Who or what initiates the task?

• Outputs- What are the performance

criteria

- What happens to the output?

- How does that task performerget feedback about taskperformance?

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Questions to AnswerAbout the Task

• The process oftransformation- What is the nature of decision

making

- What strategies exist fordecision making

- What skills are needed.

- What interruptions are likely tooccur? When?

• Task composition- How often is it done and

when?

- Is it dependant on other tasks?

- What is normal/abnormalworkload?

- What control does the taskperformer have over workload?


Notation for Recording,UML Activity Diagrams

• Use fork/join torepresent parallel orunordered activities

• An activity in a fork/joinis optional if labeled witha [condition]

• An activity may containa more detailed activitydescription, mark withan (*)

Activity

start

fork

ConcurrentActivityActivity Activity

join

branch

merge

end

[condition] [else]




Example Task Analysis

PDA Controller for Copiers

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Example, the Copier Control

• User goals become the top level tasks.

• From the question “What do you do?”- Make single copies of individual documents.

- Create two-sided copies of one-sided documents or articlesfrom books.

- Make one-sided copies of articles as masters for coursecompendiums

- Make compendiums.


Refine the Top-Level

• Remember, exact duplication is most frequent.

• Note, making compendium masters is a subset ofconverting book articles to two-sided copies for reading

• Note, making compendiums and copying one-sidedarticles to two sides are the same task.

• New subtasks- Make one-sided “masters” from books.

- Make two-sided copies from one-sided originals


Top-Level Activity Diagram

1-Sided Mastersfrom Books*

SingleCopies*

2-Sided Copiesfrom Paper*

[make compendium,2-sided article]

[compendium masters]

1-Sided Mastersfrom Books*

[2-Sidedfrom Books]

2-Sided Copiesfrom Paper*

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One-Sided Masters

Setup Copier*

Copy RelevantPage Pairs

Check Pages

Cull UnwantedPages


Things to Consider

• Are intermediate paper copies (compendium masters)necessary or an artifact of the existing method?

• Would the user like to save setups?

• Should the simple duplicate function be easiest toaccess?

• What else can be done with a PDA to simplify the task?


Summary

• Traditional software development

• External analysis

• Task analysis

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Questions?

Documents

External and Task Analyses · Personae •There are usually several personae •Choose one as the principle or head persona-Whose goals are the most important?-Whose goals subsume