Week 1 lecture, CN5111 Usability Engineering (2014-15)

1. CN5111 – Week 1: Lecture
Dr. Andres Baravalle

2. Timetable clash warning! (resit
students only)
• CN5111 clashes with CN6111
Enterprise Architecture
• If you are a Computing for Business
student please replace CN5111 with
CN5108 System Administration (lecture
starting at 11:00)
• If you are studying on a different
programme, please seek advise from your
programme leader.

3. 3
Lecture content
• Module introduction (team, aims, learning
outcomes and structure)
• Module logistics
• Introduction to Usability Engineering
• Teaching schedule
• Measuring the user experience

4. Module introduction

5. Module team
• Andres Baravalle
5

6. Module aims
• To provide students with the knowledge
and understanding of the basic concepts
and principles of human factors in the
design of computer interfaces
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7. Learning outcomes
• Knowledge
– Identify current research and practices in the development of
usable and accessible software systems
• Thinking skills
– Effectively evaluate the usability of software systems and make
appropriate design decisions
• Subject-based practical skills
– Embed usability in the software design process
• Skills for life and work (general skills)
– Read texts critically and be able to paraphrase, reference and
quote correctly
– Support own analysis with relevant theory
7

8. Module handbook
• Your handbook includes information on:
– Module organisation
– Learning support
– Reading and resource list
– Teaching schedule
– Assessment
• Please familiarise yourself with the
handbook!
8

9. Module logistics

10. Module organisation
• 2 hour lecture
• 2 hours practical/workshop
– Under normal circumstances, there will be no
breaks in the practical
10

11. Practical groups
• There is only one practical running

12. CN5111is a green module
• You will not receive a printed copy of your
handbook
• You will not receive printed notes/slides
• You will not have to hand in any printed work
and you will have a on-line submission
– Submission at the helpdesk will NOT be available
– You will receive on-line feedback for you assessment
(and will have the opportunity to receive personal
feedback)

13. Readings and resources for the
module
• The core text book for this module is
– Albert, W. and Tullis, T. (2013) Measuring The
User Experience: Collecting, Analyzing, And
Presenting UX metrics. 2 Edn. Morgan
Kaufmann.
• A list of recommended readings is
included in the Module specifications at
the end of your Module Handbook

14. Research based
• This module draws both on recent
research and on material developed for
the module itself
• Make sure that you read both the book
and the slides – and that you use them to
study
– The core text book, the teaching material and
the assignment are updated frequently

15. Research based (2)
Smith-Atakan, S. (2006) Human
Computer Interaction. 1st edn.
Sharp, H., Rogers, Y. and
Preece, Y. (2011) Interaction
design: beyond human-computer
interaction. 3rd edn.

16. Moodle
• Slides, teaching material, module
handbook are ALL on Moodle
• The teaching material on Moodle might be
updated during the semester
– Keep an eye for updated documentation
• The assignment will be released in week 2
16

17. Introduction to Usability
Engineering

18. Usability in context
• Usability is a wide research field that
involves researchers from different
disciplines such as:
– Communication Science, Psychology and
Sociology
– Computer Science and Engineering
– Human Computer Interaction and
Ergonomics.
18

19. Usability definitions: IEEE 90
• "The ease with which an user can learn to
operate, prepare inputs for, and
interpret outputs of a system or
component." (IEEE 90).
19

20. Usability definitions: ISO 9241
• "The extent to which a product can be
used by specified users to achieve
specified goals with effectiveness,
efficiency and satisfaction in a specified
context of use." (ISO 9241).
20

21. Usability definitions: ISO 13407
• "The usability of an interface is a measure
of the effectiveness, efficiency and
satisfaction with which specified users
can achieve specified goals in a
particular environment with that
interface." (ISO 13407).
21

22. Usability definitions: summary
• The first definition stresses the "easy of use" of a system
and the actions that should be easily performed
(operating with a system, preparing input, interpreting
output).
• The second definition states that usability is not a
generic concept, but that it is specific to individual users
and contexts. It also clarifies that the goals for which a
product is used have to be achieved with effectiveness,
efficiency and satisfaction.
• The third definition is very similar to the second, but
stresses that usability is a measure of a condition, not a
static property of an artefact.
22

23. Usability definitions: summary
(2)
• The next slides focus on defining with
more accuracy the core terms used in the
usability definition(s):
– Interface
– Effectiveness
– Efficiency
– Satisfaction

24. Interface
• A interface is the means by which
interaction is achieved
– E.g. The keyboard is one of the possible
interfaces for a PC
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25. Effectiveness
• Effectiveness: each user has a particular
goal to achieve when using an interface.
• Effectiveness measures if the expected
goals have been achieved and measures
the accuracy and completeness of the
specified goals.
25

26. Efficiency
• Efficiency: measures the effort necessary
to achieve the user’s goal and if it is
proportionate to the expected result.
26

27. Satisfaction
• Satisfaction: measures the pleasantness
of using a particular interface and if the
interface is suitable or not for the desired
goal.
27

28. Usability roots
• While it can be difficult to find the "first" usability study
we can find interests in usability that can be dated at
least to classic authors.
• Greek and Roman authors were already aware of the
problems related to Ergonomics, but we cannot find a
systematic exposition of the issues.
• The environment and its relation to worker health were
recognized as early as the fourth century BC when
Hippocrates noticed lead toxicity in the mining industry
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29. Usability Roots: Bernardo
Ramazzini
• “The maladies that affect the clerks arise
from three causes: first, constant sitting;
secondly, incessant movement of the hand
and always in the same direction; and
thirdly, the strain on the mind.”
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30. Usability Engineering
• Usability Engineering is the discipline that
focuses on implementing and assessing
the usability of an interface.
30

31. Teaching schedule
• See the handbook on Moodle

32. Measuring the user experience
• The next slides are based on the content
of your core text book
• Check your reading plan in the teaching
schedule!

33. This is a practical module!
• This modules aims to be a practical, how-
to guide about measuring the user
experience

34. What are user experience (UX)
metrics?
• A metric is a "system or standard of
measurement" (Oxford dictionary)
• We can say that something is longer,
taller, or faster because we are able to
measure or quantify some attribute of it,
such as distance, height, or speed.
– The process requires agreement on how to
measure these things, as well as a consistent
and reliable way of doing it

35. UX metrics
• UX metrics are based on a reliable system
of measurement
• Must be observable
• Require an aspect of the user experience
that is quantifiable
– It's normally related to the effectiveness,
efficiency or satisfaction of a user interacting
with an interface

36. UX metrics examples
• Quantitative:
– Time
– Key presses
– Number of errors
• Qualitative
– User satisfaction
– User enjoyment
• None measures usability directly!
36

37. Why UX metrics?
• Without the insight provided by metrics,
important business decisions may be
made based on incorrect assumptions,
“gut feelings” or hunches
– It’s fairly easy to spot some of the more
obvious usability issues, but it’s much harder
to estimate the size or magnitude of the
issues

38. Why UX metrics? (2)
• User experience metrics show:
– Whether you’re actually improving the user
experience from one version of a product to
the next
– How you compare to your competitors

39. Why UX metrics? (3)
• User experience metrics can help reveal
patterns that are difficult to see.
– For example, sometimes it’s difficult to see
small inefficiencies, such as the need to re-
enter user data
– Many small inefficiencies can eventually build
up to impact the user experience

40. More on metrics
• Metrics can be collected easily as part of a
normal iterative usability evaluation
• Reliable metrics can be collected as part
of normal testing
• UX metrics are useful for large and small
projects alike
• Well designed experiments can avoid
common noise effects (E.g. user went for
a cup of tea during the experiment)

41. More on metrics (2)
• Having data takes a lot of the guesswork
or gut feelings out of usability decisions
• Metrics are important for new and
established products alike
• There are metrics for most aspects you
think are crucial for your product –
including emotional response!

42. More on metrics (3)
• Metrics provide credibility to the team, the
product, and the design process
• Smaller sample sizes of 8 or 10
participants can still be meaningful