External and Task Analyses. Overview. Traditional Software Development. SMD157 Human-Computer Interaction Fall 2005

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

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INSTITUTIONEN FÖR SYSTEMTEKNIK

LULEÅ TEKNISKA UNIVERSITET

External and Task Analyses

SMD157

Human-Computer Interaction

Fall 2005

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Overview

• Traditional software development

• External analysis

• Example external analysis

• Task analysis

• Example task analysis

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The Software Life Cycle:

Six Phases

Requirements Definition Specification Implementation Testing Installation Maintenance

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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

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Unusable Systems

• Why?

- The non-technical is very important. - Remember the Vincennes

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External Analysis

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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

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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!

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Create fictional users

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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 feel

stupid

- Don’t want to work too hard - Want to get the job done, not

fight with the computer - Want to get done and do

interesting stuff, like ski!

• Work goals:

- Want workers to accomplish the maximum - Want to do it cheaply - Want workers to accomplish a

set of tasks (e.g., sell insurance)

- Hereafter, work goals will be called tasks.

User goals and work goals are not the same.

The system cannot violate user goals and

must 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, ...)

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Example, Air Traffic Control

• The British Aviation Authority decide to upgrade the air

traffic 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 solution

preferred?

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

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Example, a Crime Statistics Reporting System

• Was deployed in Northern England primarily to provide

management 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 crowded

environment

• 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

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Environment, Example

• Underwater PC • Problem: - Not waterproofing - Interaction • Why:

- One hand free - Noise disturbs voice

recognition

- 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 appointment

is made.

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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, use

recursively. • Finds out the outside

influences. • Examines product or

purpose. • 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 actually

prefer when the system is implemented are often

different.

- Evaluation with out the experience is dubious

• People away from the work environment and the task

don’t remember much or accurately.

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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

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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

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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

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Storyboard

Example

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

2. In the morning of the first day, Håkan gets an intro-duction to the problem areas by the client’s own network optimizers.

3. Customer complaints tell Håkan where to look, but in order to pinpoint the p rob-lematic cell(s), he and t he other optimizers take a TEMS, 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 wireless

connection

• 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 the control panel

• Design a PDA program to accomplish the goals.

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Personae

• The main persona is a teacher

- Håkan

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

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

• 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 of

one-sided documents or articles from books. - Make one sided copies of

articles as masters for course compendiums

- Make compendiums.

• Why?

- I need an extra copy. - To read on the plane, because

they are lighter and less bulky. - Single sheet feed, 1-sided to

2-sided is the fastest mode to produce the lest bulky 2-sided copies.

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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

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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 the article

• Corrections

- Hand staple - Redo - Clear and redo - Copy them and sort

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One Might also Ask

How Often?

• Make single copies of

individual documents. • Create two-sided copies of

one-sided documents or articles from books. • Make one sided copies of

articles as masters for course compendiums

• Make compendiums.

• Often, half of the time • Frequently

• Once or twice per term, but there are many articles.

• Only, if I must.

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Task Analysis

• Organization of user interaction with the system into:

- Tasks (work goals)

- Methods

• Constructs a model of user/system interaction

- Usually hierarchically composed

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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 of

user tasks.

• Refine the task analysis until you have a description of

what each user must know to perform each task.

• You must have this information available when the user

needs it. This will influence your display designs.

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Input

Typical Task

Transformation _Output

Questions to Answer

About the Task

• Inputs

- What information is needed? - What are the characteristics of

the information sources? (reliable?, in needed form?) - What is the availability of the

information?

- Who or what initiates the task?

• Outputs

- What are the performance criteria

- What happens to the output? - How does that task performer

get feedback about task performance?

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Questions to Answer

About the Task

• The process of

transformation

- What is the nature of decision making

- What strategies exist for decision making - What skills are needed. - What interruptions are likely to

occur? When?

• Task composition

- How often is it done and when?

- Is it dependant on other tasks? - What is normal/abnormal

workload?

- What control does the task performer have over workload?

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Notation for Recording,

UML Activity Diagrams

• Use fork/join to

represent parallel or unordered activities • An activity in a fork/join

is optional if labeled with a [condition] • An activity may contain

a more detailed activity description, mark with an (*) Activity start fork Concurrent Activity Activity Activity join branch merge end [condition] [else] INSTITUTIONEN FÖR SYSTEMTEKNIK

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 articles from books.

- Make one-sided copies of articles as masters for course compendiums

- Make compendiums.

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Refine the Top-Level

• Remember, exact duplication is most frequent.

• Note, making compendium masters is a subset of

converting book articles to two-sided copies for reading

• Note, making compendiums and copying one-sided

articles 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 Masters

from Books* 2-Sided Copies_{from Paper*} Copies*Single

[make compendium, 2-sided article] [compendium masters] 1-Sided Masters from Books* [2-Sided from Books] 2-Sided Copies from Paper*

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One-Sided Masters

Setup Copier* Copy Relevant Page Pairs Check Pages Cull Unwanted Pages