Got Data, Now What?Analyzing Usability Study Results

Lynn Silipigni ConnawayJune 26, 2005

Presented at the ALA 2005 Annual Conference Chicago, ILLAMA/MAES Using Measurement Data for Library Planning and Assessment Committee

Usability Testing: Why?

“Probably the best reason to test for usability is to eliminate those interminable arguments about the right way to do something. With human-factors input and testing, however, you can replace opinion with data.  Real data tend to make arguments evaporate and meeting schedules shrink.” (Fowler, 1998, Appendix, p. 283)

Usability Testing: Definition

Degree to which a user can successfully learn and use a product to achieve a goal

Research methodology• Evaluation• Experimental design

Observation and analysis of user behavior while users use a product or product prototype to achieve a goal (Dumas and Reddish, 1993, p.22)

“User-centered design” process involving user from initial design to product upgrade (Norlin and Winters, 2002)

Approach is to be a servant to the users of a system NOT to be subservient to technology (Gluck, 1998)

Goal is to identify usability problems and make recommendations for fixing and improving the design (Rubin, 1994)

Usability Testing: Background

Relatively new methodology (Norlin and Winters, 2002)• Origins in aircraft design• Traced back to marketing

• Development of a product• Popular in 1980s with widespread access to computers• Initiation of human computer interface usability studies• Evolved from human ethnographic observation,

ergonomics, and cognitive psychology• Qualitative and quantitative data

Usability Testing: Purpose

Evaluation tool Identify problem areas “Determine the fit of the design to the intended users”

(Norlin and Winters, 2002, p. 5)

Usability Testing: Suitable Questions

What is the best layout for a web page? How can you optimize reading from PDAs and small screen

interfaces? Which online fonts are the best? What makes an e-commerce site difficult to use? Can individual personality or cognitive skills predict Internet

use behavior? How can library collection holdings and library data be

represented geographically?

Usability Testing: Principles

Keep the end user in mind Achieve superiority through simplicity Improve performance through design Refine and iterate (Norlin and Winters, 2002, p.10)

Usability Testing: Web Design Criteria

Links must be consistent and predictable Group like things on the same page  Be consistent with language Most important information should be on the first screen Provide keywords for quick reading/scanning Do not use animation or sounds Make links look like links Distinguish text from graphics Avoid jargon (Spool, 1999)

Usability Testing: Web Design Criteria

Ten Usability Heuristics (Nielsen)• Visibility of system status • Match between system and the real world• User control and freedom • Consistency and standards • Error prevention • Recognition rather than recall • Flexibility and efficiency of use • Aesthetic and minimalist design • Help users recognize, diagnose, and recover from errors • Help and documentation

Usability Testing: Web Design Criteria

Goals for user-centered design• Enable users to

• Achieve their particular goals and meet their needs • Move quickly and with few errors

• Create a site that users like• More likely to perform well on a product that provides

satisfaction

Usability Testing: Methodology

Artificial environment (laboratory)• Maintain more control• May provide more specific data on a particular feature

Natural environment• Better holistic representation of real people doing real

work

Usability Testing: Methodology

Four types of usability tests (Rubin, 1994, p. 31-46)• Exploratory test – early product development• Assessment test – most typical, either early or midway

in the product development• Validation test – verification of product’s usability• Comparison test – compare two or more designs; can be

used with other three types of tests

Usability Testing: Methodology

Develop problem statements, objectives, and/or hypotheses Identify and select participants who represent target population

• May or may not be randomly selected Select test monitor/administrator

• Empathetic• Impartial• Good communicator• Good memory• Able to follow test structure• Able to react spontaneously to situations that cannot be

anticipated• Allow user time for task• Don’t rescue the user• Continue with the plan if mistakes occur

Usability Testing: Methodology

Design test materials• Screening questionnaire

• Provides user profile• Ascertains pretest attitudes and background

information• Provides information about participants’ previous

knowledge and experience• Orientation script

• Describes the test to participants• Aids in understanding the participants’ performance

• Data logger materials• Data collection instrument for categorizing

participants’ actions• Can note time to match with videotape recording

Usability Testing: Methodology

Design test materials• Non-disclosure and tape consent forms for legal

protection• Task list

• List of actions participants will execute• Desired end results• Motives for performing task• Actual observations monitor will record• State of system

Usability Testing: Methodology

Design test materials • Posttest questionnaire

• All participants asked the same questions• Gather qualitative information and precision

measurements• Debriefing guide

• Structure and protocols for ending the session• Participants explain things not apparent in actions

• Motive• Rationale• Points of confusion

Usability Testing: Methodology

Test materials and equipment Conduct the test

• Represent the actual work environment• Users are asked to think aloud• Observe users while using or reviewing the product

• Probe• Controlled and extensive questioning

• Collect quantitative and qualitative data and measures• Record comments or questions about the product• Observe and document users’ behaviors

Usability Testing: Methodology

Debrief Analyze the data

• Diagnose and recommend corrections • Categorize and identify problems with the product• Identify solutions

• Qualitative analysis• Textual notes from debriefing• Read responses• Summarize findings

Usability Testing: Methodology

Analyze the data • Quantitative analysis

• Questionnaires• Screening• Posttest

• Triangulation to validate findings• Data from questionnaires, observations, screen

tracking software, comments, and open-ended questions

Usability Testing: Interpret Data

Interpret the data• Five factors for benchmarking the usability of an

interface (Shneiderman and Plaisant, 2004)• Time to learn• Speed of performance• Rate of errors• Retention over time• Subjective satisfaction

Usability Testing: Interpret Data

Interpret the data • Prioritize severity of problems

• Severity ratings (Zimmerman and Akerelrea, 2004)• Time required to complete task• Number of users who encountered problem• Negative impact on users’ perception of the

product• Difficult if 70% of users cannot perform task • Error criticality = Severity + Probability of Occurrence

(Rubin, 1994)

Usability Testing: Interpret Data

Usable Web site: (Rubin, 1994)• Usefulness

• Establish whether it does what the user needs it to do• Effectiveness

• Ease of use to achieve the desired task• Learnability

• Ease of learning application and moving from being a novice to a skilled user

• User satisfaction• User’s attitude about the site—how enjoyable it is to

use

Usability Testing: Report Results

Executive summary Report

• Describe methodology• Who, what, when, where, and how• Describe how tests were conducted• Profile users and describe sampling• Detail data collection methods

• Succinctly explain the analysis• Provide screen captures• Include tables and graphs• Provide examples

• Identify strengths and weaknesses• Recommend improvements

Usability Testing: Making the Data Work

Read report Determine what worked and what did not work Redesign product/system based upon findings May be necessary to conduct another usability test

Usability Testing: Limitations

Two major limitations (Wheat)• Reliability

• Testing of users who are not atypical users• Individual variation within the test population

• Validity • Test tasks, scenarios of the search processes, and

testing environment are not accurate • Results not generalizable to the entire user

population• Testing is always artificial (Rubin, 1994, p.27)

OCLC WorldMapTM

Research prototype• Test geographical representation of WorldCat holdings

• By country and date of publication• For library collection assessment and comparison

• Complement the AAU/ARL Global Resources Network project

• Geographically represent library statistical data from UNESCO, ARL, Bowker, and others

• Number of libraries by type• Expenditures by library type• Number of volumes and titles• Number of librarians• Number of users

http://linuxdev1.dev.oclc.org:22221/WorldMap/

Usability Testing: OCLC WorldMapTM

Review sample handouts• Screening questionnaire• Task list• Posttest questionnaire• Executive summary

Usability Testing: OCLC WorldMapTM

Conducted informal usability tests Currently redesigning the interface Conduct second group of formal usability tests Make revisions prior to making publicly available

Questions and Discussion

connawal@oclc.org