1 Human Factors 101 Nelson Soken CRM HFE Manager Systems Engineering & Human Factors.

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Human Factors 101Human Factors 101

Nelson Soken

CRM HFE Manager

Systems Engineering & Human Factors

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• What is human factors?

• Cost justification and benefits

• Overview of the process and tools• Requirements• Design• Evaluation

Human Factors 101Human Factors 101

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Human Factors: Design approach that increases product usability

Usability Testing: Part of the human factors process: Evaluation of the product concept with interface experts and actual users

Definitions of human Definitions of human factors and usability factors and usability

testingtesting

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Definitions of UsabilityDefinitions of Usability

•Usability represents a balance between the TASK, the USER, and the SYSTEM to achieve a particular PURPOSE within an environment.

•Users can achieve their goals in an effective, efficient, and satisfactory way.

•Easy-to-use, early-to-learn, user friendly, easy-to- implement, and user accessible.

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Why do we design unusable Why do we design unusable products?products?

1. Common-sense design is good enough.2. The more functionality the better!3. We can evaluate the interface later....4. We’ve always done it this way.5. My boss said I had to design it this way.6. Users can customize their interfaces any way they want.7. I’m a user!

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HFE FocusHFE Focus

• Design out the potential for human error• Design in ease-of-learning and ease-of-use

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Benefits of Human Benefits of Human FactorsFactors•Evidence shows that product usability is the

market differentiator of the future.

(Harvard Business Review, July-August 1991, A Rappaport & S Halevi)

“If you do not do usability testing on your product, then the customer will do it for you”

• Reduced Development Cost

• Increased Sales

• Increased Product Quality

• Increased Customer Satisfaction

• Reduced Service and Maintenance Costs

• Reduced Documentation

• Reduced Liability

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What HFE Brings to the What HFE Brings to the Project:Project:

Knowledge of human perception, cognition, strength, size….

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What HFE Brings to the What HFE Brings to the Project:Project:

Knowledge of human perception, cognition, strength, size….

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What HFE Brings to the What HFE Brings to the Project:Project:

Tools for design and evaluation of systems for human use

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What Does HFE Contribute?What Does HFE Contribute?

• End user profiles, needs• Use environment & workflow descriptions• User interface features, design concepts• System usability specifications Product Plan

• User interface design prototypes• Design usability testing• User interface design specifications Product Specifications

• Use error/hazard analysis• User interface design requirements•Training and documentation requirements Product Requirements

• Inputs to Clinical Study Plan• Usability testing, field usability studies Regulatory Submittals

• Human Factors input to investigation of use error events• Gathering and analysis of customer feedback Product Planning

UserResearch

ConceptualDesign

Requirement& CriteriaDevelopment

DetailedDesign &Specification

Evaluation

Deployment

Iterative Cycle

Design Controls

DesignInput

DesignOutput

Verification& Validation

RegulatoryApproval

Post-MarketSurveillance

UserResearch

ConceptualDesign

Requirement& CriteriaDevelopment

DetailedDesign &Specification

Evaluation

Deployment

Iterative Cycle

Design Controls

DesignInput

DesignOutput

Verification& Validation

RegulatoryApproval

Post-MarketSurveillance

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Key Characteristics of Key Characteristics of the the

Human Factors Human Factors ApproachApproach• Incremental, iterative development

• User focused design

• Goal-directed, evaluation-centered design

• Multi-method, empirical evaluation

• Rapid prototyping and development

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Requirements TipsRequirements Tips

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Understand the Users and Their Needs

• Who are the users?

• What needs to be done?

• What is most important?

• How is the system interaction designed?

• Who does what?

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Interaction Design TipsInteraction Design Tips

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Design/Redesign the Product Concept

• Parallel Design

• Participatory Design

• Style Guides

• Prototypes

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General Design

Interactions should be:• Predictable• Consistent• Implicit• Present Appropriate, Simple Information• Reduce Information Load• Put the User in Control

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Usability EvaluationUsability Evaluation

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What Is a Usability What Is a Usability StudyStudy• A subjective and objective evaluation of how

well a system meets the needs of its users.• System – a combination of the product, the

environment, and the user

• Needs – expectations, knowledge, skills, abilities, performance, norms…

• Users – purchasers, managers, end users, maintainers…

• Usability is an iterative process

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What Is a Usability What Is a Usability StudyStudy

Types of usability studies• Inquiry – used to obtain information about users likes/

dislikes, needs, system understanding via observation, interview, and survey• Field observation, Focus groups, Interviews and

Questionnaires

• Testing – used to identify where interface could better support user by having users work on typical tasks with the product• Performance measurement, Thinking aloud, Teaching method

• Inspection – used to identify deviation from established guidelines or standards through expert review• Heuristic evaluations, Cognitive and Pluralistic walk-

throughs, Feature and label inspections

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How Do You Prepare a How Do You Prepare a StudyStudyMap Usability Concerns to Participants

• Determine sample size• Within-subjects requires fewer participants than between-

subjects

• Usability focused on finding gross problems, statistical power less important, small frequent samples OK

* Nielsen and Landauer, 1993. A mathematical model of the finding of usability problems. Proc.

ACM INTERCHI ’93 Conference, Amsterdam, the Netherlands, 24-29 April

• Usually 5-8 participants» 4 participants will find 70% of

major usability issues

» 8 participants will find 85%, diminishing returns above 8*

• Use a larger sample if investigating a specific interface issue

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Recap: Typical HFE DeliverablesRecap: Typical HFE Deliverables

• HFE Plan

• HFE Analyses (e.g., user profiles, task analyses, use error analyses)

• User Interface (UI) Design concepts, mockups, prototypes

• UI Design Requirements

• UI Design Specifications

• Usability Testing Reports and Summaries

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ReferencesReferences

Books• Bias and Mayhew (1994). Cost-Justifying Usability. Chestnut

Hill, MA: Academic Press.

• Cooper (1999). The Inmates are Running the Asylum. Indianapolis, IN: SAMS

• Dumas and Redish (1993). A Practical Guide to Usability Testing. Norwood, NJ: Ablex Publishing.

• Mayhew (1999). The Usability Engineering Lifecycle. San Francisco, CA: Morgan Kaufmann Publishers.

• Nielsen (1993). Usability Engineering. Chestnut Hill, MA: Academic Press.

• Bogner (1994). Human Error In Medicine. Hillsdale, NJ: Lawrence Erlbaum Associates.

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ReferencesReferences

Websites• Jakob Nielsen’s site: www.useit.com

• Usability evaluation site: www.cs.umd.edu/~zzj/UsabilityHome.html

• Examples of poor product designs: www.baddesigns.com

Articles• “Get inside the lives of your customers, Patricia Seybold,

HBR, May 2001