Deciding How to Measure Usability

How to conduct successful user requirements activity?

Deciding How to Measure Usability Understanding what you can measure Matching Measures to your Goals and

concerns Matching Measures to the Product's Stage of

Development Setting Quantitative Criteria for Each

measure and each Task

Understanding what you can measure

In a usability test you measure both Performance measures and Subjective measures

Understanding what you can measurePerformance Measures: count of behaviors or actions you can see.Quantitative e.g. how many errors people make and how many times they repeat the same error

Understanding what you can measureSubjective Measures: people's perceptions, opinions and judgments.either quantitative or qualitativee.g. give a people 5 or 7 point scale and ask them to rate difficulty in using a product.

Deciding How to Measure Usability Understanding what you can measure Matching Measures to your Goals and

concerns Matching Measures to the Product's Stage of

Development Setting Quantitative Criteria for Each

measure and each Task

Deciding How to Measure Usability Understanding what you can measure Matching Measures to your Goals and

concerns Matching Measures to the Product's Stage of

Development Setting Quantitative Criteria for Each

measure and each Task

Matching Measures to your Goals and Concerns

Performance measures chosen should be directly related to quantitative usability goals and concerns behind the usability test

How to collect performance data?

Data Logging Software

S... Stop the test B Take a BreakT... Stop the task A Assist

M Menu Error H Help deskS Select from list error F FrustrationE Other Error N Observations

Event: O 06:21:33

Comment: Looking for online help for To: field

Points to be considered in building Data Logging Program

Include preset codes for events that happen in every test.

Code should be small Short description with code Timestamp every event Allow easy backup and movement of data into a

fileWhat if you don't have a data logging software?Should you measure positive behavior?

Deciding How to Measure Usability Understanding what you can measure Matching Measures to your Goals and

concerns Matching Measures to the Product's Stage of

Development Setting Quantitative Criteria for Each

measure and each Task

Matching Measures to Product's stage of development

Very important to consider where product is in the development cycle while planning performance measures.

Testing prototype for a manual (without index)

Deciding How to Measure Usability Understanding what you can measure Matching Measures to your Goals and

concerns Matching Measures to the Product's Stage of

Development Setting Quantitative Criteria for Each

measure and each TaskChoose the performance measures you want to

count

Selecting Performance MeasuresGeneral Concerns: Ease of users who have never used email Ease of users who have used other email Will the online help be useful Will new user be able to select items from

screens quickly and easily

Selecting Performance Measures

Specific Concerns: Will the user be able to read a specific piece

of mail and skip over mail they don't want to read

Will new users be able to find and select people's addresses to send them mail

Will users be able to find the right menu path to read/write/send a message

Setting Quantitative measure for Each Measure and Task

How to select criteria for performance measures?

Typical criteria for Performance measures Excellent Acceptable or OK Unacceptable

Base your criteria on users

Setting Quantitative Criteria for each measure and each task

Measure Excellent Acceptable UnacceptableTask 1: Read MessageTime for Task <3 min 3-5 >5Time in online help

<1 1-2 >2

Write and SendTime for Task <10 min 10-15 min >15 minTime in online help

<2 2-4 >4

E=Other Errors 0 1-2 More than 2

Are the measures the same for all tasks in a given test?

NoAre the criteria of performance same for all

tasks? No

Do you take the test situation into account in selecting criteria?

YesShould you count system response time in

setting the criteria? Yes

What we have discussed till now

Tasks that participants will do during tests and how to measure participant's performance with products.

Deciding How to Measure Usability

How to conduct successful user requirements activity?

How to conduct successful user requirements activity?

Welcoming your participants Dealing with late and absent participants Warm up exercises Inviting Observers Introducing your think aloud protocol Moderating your activity Recording and note taking Dealing with awkward situations Conclusion

Welcoming your participants

Ask participants to come about 15 minutes earlier.

Introduction. Welcome Signs. Playing CDs.

Don't leave participants alone

Dealing with late and absent participants

Despite your best efforts some participants can be late.The late participantYou can't wait any longerIncluding late participantsThe No-Show

Warm-up ExercisesStart with light conversation.Introduce yourself.Provide nametags

Don't spend much time

Inviting Observers

Developer observers get to know user requirements better.

Tell observers to come early and remain quiet.

Don't allow managers to observe

Introducing your think aloud Protocol

Make participants speak Their thought process while doing task . Steps in the task. Expectations and evaluation statements.Provide some examples to participants e.g. Stapler Observe loudness of participants

Moderating your activity Have personality Ask questions Stay focused You are not a participant Keep activity moving No critiquing Everyone should participate No-one should dominate Practice makes perfect

Take Notes You get data immediately and can start

analysis Participants feel they are saying important

thingsProblems: You can get wrapped being a stenographer If discussion pace is fast all information

cannot be captured

Video and Audio Recording Capture nuances, body language of

participants (cant have in notes) Listen to recording and take notes Video better than audio recordingProblems: Can make participants uncomfortable

What is the best approach?

Combine Video/Audio Recording and Notes

Dealing with awkward Situations

Some Uncomfortable situations and ways to deal with them :Participant Issues Observers Issues

Participants Issues

Participant is called in middle of test Participant's cell phone rings continuously Wrong participant recruited Participant thinks he is on a job interview Participant refuses to be videotaped and

wants to leaveContd..

Participants Issues

Participant is confrontational with other participants

Participant dominates the group Participant is not truthful about his identity Participant refuses to sign consent form Fire Alarm sounds in middle of test and

participant still wants to continue

Product Team/Observers Issues Team changes the product mid-test An observer turns on light in control room Observers talk loudly during an activity

Conclusion

To conduct any of your user requirements effectivelyDeal with participant arrivals. Make them think creatively. Moderating any activity Instruct your participants to think aloud.Deal with any awkward situation in testing that may arise.