Scenario-Based Usability Engineering

Chris North

cs3724: HCI

Homework #0: UI Analysis

• See website

• Pick a movie of your choice

• Task: find a convenient playing time and location

• Use 3 different systems:• 1-800-555-TELL

• www.moviefone.com

• www.hollywood.com/showtimes/

• Write down the time it takes you for each

• Bring your times to class on Thursday

Homework #0

• Qualitative discussion• Usability problems, errors, access, alternate tasks, …

• Quantitative discussion• Data averages, min, max

• Data visualization

• Statistics, t-tests, …

Myth

• The user interface is tacked on at the end of the project

The Changing Face of Computer Use

1960’s

1970’s

1980’s

1990’s

2000+

Professional programmers,“software psychology”

Business professionals,mainframes, command-line

Large, diverse user groups,“the computer for the rest of us”

World Wide Web and more,information access & overload

Ubiquitous computing,diversity in task, device, …

Newton vs. Palm

• Newton

• Palm

User Interface Metrics

• Ease of learning•

• Ease of use•

• User satisfaction•

Not “user friendly”

Tradeoffs

• Optimization?

• Examples

• Identify tradeoffs

• Choose based on design goals

• Track tradeoffs for rationale

Using “Scenarios”

Marissa was not satisfied with her class today on gravitation and planetary motion. She is not certain whether smaller planets always move faster or how a larger or denser sun would alter the possibilities for solar systems.

She stays after class to speak with Ms. Gould, but she isn’t able to pose these questions clearly, so Ms. Gould suggests that she re-read the text and promises more discussion tomorrow.

Stories about people and their needs, activities

A problem scenario describing current situation:

Marissa , a 10th-grade physics student, is studying gravity and its role in planetary motion. She goes to the virtual science lab and navigates to the gravity room.

In the gravity room, she discovers two other students, Randy and David, already working with the Alternate Reality Kit, which allows students to alter various physical parameters (such as the universal gravitational constant) and then observe effects in a simulation world.

The three students, each of whom is from a different school in the county, discuss possible experiments by typing messages from their respective personal computers. Together they build and analyze several solar systems, eventually focusing on the question of how comets can disrupt otherwise stable systems.

They capture data from their experiments and display it with several visualization tools, then write a brief report of their experiments, sending it for comments to Don, another student in Marissa’s class, and Mr. Arkins, Randy’s physics teacher.

A design scenario describing our initial vision:

Scenario Elements

• Setting

• Actors (people, users)

• Task goals (what I want to achieve)

• Plans (how I will accomplish it)

• Actions (do it)

• Events (system response)

• Evaluation (is that what I wanted?)

Advantages of Scenarios

Problem scenarios

summativeevaluation

Information scenarios

claims about current practice

analysis ofstakeholders,field studies

Usability specifications

Activityscenarios

Interaction scenarios

iterativeanalysis ofusability claims andre-design

metaphors,informationtechnology,HCI theory,guidelines

formativeevaluation

DESIGN

ANALYZE

PROTOTYPE & EVALUATE

Iterative

• Fuzzy -> clear

Iterative

• Fuzzy -> clear

Iterative

• Sometimes “design is radically transformational”

Summary

• Measurable Metrics!

• Tradeoffs

• Scenarios, elements

• Scenario-based UE process

• Iterative

• assignment:• Download & install java sdk1.4, Borland JBuilder

• Read Ch 2

Presentations

• Groups of 2

• 5 minutes, 2-3 slides

• Pick UI of your choice (software or real-world)

• UI critique• Scenarios/tasks

• Good

• Bad

• Redesign ideas?

• Vote: UI Hall of Fame/Shame

Fast Food Drive-Thru Menus

• Scenarios:• College student

• hungry

• Get food, get out. FAST!

• Often: sandwich, fries, drink

• Typically: Not sure what I want

• Sometimes: Know what I want

• Passengers want food too

• Limited budget

The Good

• All in one view

• Organized by categories

• Tabular format: left alligned, prices alligned

• Combo meals (high frequency)

• Get price before proceeding

• Some: feedback on order

Need picture!

The Bad

• See menu too late

• Passengers cant see menu

• Passengers must order thru driver

• Winter: brrrrr…

• Small Redesign ideas:• More menus back in line

• Menu on both sides of car

• Microphone on both sides

• Radical: cell phone, in-car UI

The Ugly

• I can’t understand a word they say

• They cant hear me over my ’87 VW