Slide 1

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

Evaluation, Usability Testing!

Slide 2

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

A simple development process!

Establishing requirements

Evaluating

Prototyping

Designingalternatives

Final Product

Slide 3

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

Usability Goals – Principles!

•  Usability Goal—Easy to use – Most people are interested in completing their tasks and

do not enjoy struggling with the tools they need to use. One of the most important goals of user-centered design is to make things easy to use.

•  Design Principle—Simplicity – Simple things require little effort and can often be

accomplished without much thought. If interaction designs are guided by the principle of simplicity, they will be easier to use.

Slide 4

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

What is Usability?!

•  Ease of learning—How fast can a user learn to accomplish basic tasks?

•  Efficiency of use—How fast can an experienced user accomplish tasks?

•  Memorability—Can a user remember enough to use it effectively the next time?

•  Error frequency and severity—How often do users make errors, how serious are these errors, and how do users recover from these errors?

•  Subjective satisfaction—How much does the user like using the system?

Slide 5

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

Usability in Practice!

•  Donald A. Norman and teapots

Slide 6

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

•  The first example probably fulfills every requirement that we have given. But usable?? No.

•  The second example also fulfills the requirements but have other kinds of usability problems.

Slide 7

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

What to evaluate!

•  Design proposal •  Early prototype •  Nearly finished prototype •  An existing product •  A conceptual model

Slide 8

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

Where?!

•  In the natural settings for the user •  In a labb setting

Slide 9

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

Design the Test!

•  Why: Define the Purpose •  What: Define Your Concerns and Goals •  What: Define the Tasks •  What: Create the Scenarios •  What: Define the Measurements •  How: Define the Test Method

Slide 10

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

How!

•  Observations – For a given task, measure mouse clicks, errors made etc. – Use “Think aloud”

•  Surveys (i.e ask users and/or experts) •  Interviews

Slide 11

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

10 Usability Heuristics for User Interface Design

!•  From Jacob Nielsen http://www.nngroup.com/articles/ten-usability-heuristics/ •  Heuristics are more of rule of thumb

Slide 12

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

Nielsen. cont.!

•  Visibility of system status Always show what the system is doing – For instance, show a simple progress bar

•  Match between system and the real world The the language of the users

•  User control and freedom Emergency exits, undo, redo – E.g. a home button on a webpage

Slide 13

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

Nielsen. cont.!

•  Consistency and standards Follow the the conventions of the platform, use the same words – E.g. use the menu alternatives and shortcuts that already

exist, don’t invent new ones •  Error prevention

Try to prevent errors, forgiving input formats – E.g. use dropdown menus for choosing values

•  Recognition rather than recall Give the user info how to do things – E.g. autocompletion of words

Slide 14

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

Nielsen. cont.!

•  Flexibility and efficiency of use – Let experienced user use acceleratorn (short cuts)

•  Aesthetic and minimalist design •  Help users recognize, diagnose, and recover from errors

– Don’t just say ERROR, show an example of a correct answer, for instance how to write a date

•  Help and documentation – Tooltips, a clickable ?, introduction videos etc.

Slide 15

Lennart Petersson

Use

r Int

erfa

ce

and

Dat

abas

es

HT1

4

UIDB

Nielsen. cont.!

See also: http://designingwebinterfaces.com/6-tips-for-a-great-flex-ux-part-5 The same heuristics applied in an web centric context and with many examples.