User interface prototype wireframe part 2
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381Week9Uabilitytestingpracticalissues.pptxUsability testing
Practical considerations
A usability test is not an interview
Read the recent three page article about usability tests.
How is this similar or different to the Krug test?
2. Think about both sources (Krug & Hertzum) and the DECIDE framework
what are the practical issues that need to be considered for usability testing
what do you need to prepare?
what do you need to organise?
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A usability test is not an interview
Think about Krug,
Hertzum and the DECIDE framework
what are the practical issues that need to be considered for usability testing
what do you need to prepare?
what do you need to organise?
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A usability test is not an interview
Why is a usability test not an interview?
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Evaluation framework
Identify the practical issues.
Who
What
When
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D E C I D E
Where
How
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Reference Ch 13 Preece Rogers & Sharp, 2007
Usability testing
Involves recording performance of typical users doing typical tasks.
Controlled environmental settings.
Users are observed and timed.
Data is recorded on video & key presses are logged.
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Mobile Usability Testing: http://patterns.littlespringsdesign.com/index.php/Mobile_Usability_Testing_on_a_Budget
Usability testing
Data is used to calculate
performance times, and to
identify & explain errors.
User satisfaction is evaluated
using questionnaires & interviews.
Field observations may be used to provide contextual understanding.
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Mobile Usability Testing: http://patterns.littlespringsdesign.com/index.php/Mobile_Usability_Testing_on_a_Budget
The discipline of usability is concerned with prediction. Usability practitioners make predictions about how people will use a website or product; about interaction elements that may be problematic; about the consequences of not fixing usability problems; and, on the basis of carefully designed competitive usability tests, about which design a sponsor might wisely pursue. Predictions must go beyond the behaviour and opinions of a test sample.
we can have a known degree of confidence in the predictive value of our data only if we have applied appropriate analyses.
Usability experts collect both qualitative data (usually during early contextual research and during formative usability testing when identifying usability problems) and quantitative data (usually during summative testing when measuring the usability of a system). In both cases they typically focus on collecting data that are objective and that result from observable user behavior.
Usually both are required to get a full understanding of a user's experience with a product or system
Source: http://www.userfocus.co.uk/articles/datathink.html
Understanding data
| Quantitative | Qualitative | |
| Objective | "The chip speed of my computer is 2 GHz" | "Yes, I own a computer" |
| Subjective | "On a scale of 1-10, my computer scores 7 in terms of its ease of use" | "I think computers are too expensive" |
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Usability experts collect both qualitative data (usually during early contextual research and during formative usability testing when identifying usability problems) and quantitative data (usually during summative testing when measuring the usability of a system). In both cases they typically focus on collecting data that are objective and that result from observable user behavior.
Usually both are required to get a full understanding of a user's experience with a product or system
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Measures
Time to complete a task.
Time to complete a task after a specified time away from the product.
Number and type of errors per task.
Number of errors per unit of time.
Number of navigations to online help or manuals.
Number of users making a particular error.
Number of users completing task successfully.
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http://www.userfocus.co.uk/resources/datalogger.html
Usability testing
Goals & questions focus on how well users perform tasks with the product.
Comparison of products or prototypes common.
Focus is on time to complete task (input) & number & type of errors. (accuracy)
Data collected by video & interaction logging.
Testing is central.
User satisfaction questionnaires & interviews provide data about users’ opinions.
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Usability engineering orientation
Aim is improvement with each version.
Current level of performance.
Minimum acceptable level of performance.
Target level of performance.
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Materials - Usability lab
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Usability lab with observers watching a user & assistant
Portable equipment for use in the field
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Click to edit Master text styles
Second level
Third level
Fourth level
Fifth level
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Recording Observations
Recording user actions for later analysis?
–forgetting, missing, or misinterpreting events
paper and pencil
primitive but cheap
observer records events, comments, and interpretations
hard to get detail (writing is slow)
2nd observer helps…
audio recording
good for recording think aloud talk
hard to tie into on-screen user actions
video recording
can see and hear what a user is doing
one camera for screen, rear view mirror useful…
initially intrusive
Boring!
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Tools
Datalogger
http://www.userfocus.co.uk/resources/datalogger.html
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Tools
Camtasia
Free screen capture recording technology
http://www.techsmith.com/download/camtasia/
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Source: http://www.techsmith.com/download/camtasia/
Find others here: http://www.webresourcesdepot.com/10-free-screen-recording-softwares-for-creating-attractive-screencasts/
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Testing conditions
Usability lab or other controlled space.
Emphasis on:
selecting representative users;
developing representative tasks.
Tasks usually last no more than 30 minutes.
The test conditions should be the same for every participant.
Informed consent form explains procedures and deals with ethical issues.
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How many participants?
a practical issue.
depends on:
schedule for testing;
availability of participants;
cost of running tests.
typically 5-10 participants.
some experts argue that testing should continue until no new insights are gained.
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Explore the practical resources
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These resources can help with planning and carrying out your tests
http://sensible.com/downloads-rsme.html
http://www.usability.gov/how-to-and-tools/methods/running-usability-tests.html
http://www.userfocus.co.uk/articles/usability_test_plan_dashboard.html
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