- Usability refers to the capability of a system to enable users to achieve goals effectively and efficiently while using the system. It is related to concepts like ease of use and user experience. - Ensuring usability, or "quality in use", involves testing systems with real users performing real tasks in real contexts to identify usability issues. Both qualitative and quantitative methods are used. - Common usability testing methods include lab studies, field studies, and collecting standardized usability metrics from users. Processes like the Usability Maturity Model can help organizations systematically manage usability.

1. Usability – Assuring Quality in Use
Marko Nieminen
Professor of Usability and User Interfaces, D.Sc.(Tech.)
Aalto University School of Science
Department of Computer Science and Engineering
SoberIT - Software Business and Engineering Laboratory

2. Test and Testing
• A qualitative or quantitative procedure that consists of
determination of one or more characteristics of a given
product, process or service according to a specified
procedure
• Why testing? For instance,
• Determine if, or verify that, the requirements of a
specification, regulation, or contract are met
• Decide if a new product development program is on track:
Demonstrate proof of concept
• Validate suitability for end-use

3. Quality in Use – Related to Usability and
User Experience
The capability of a system
to enable specified users
to achieve specified goals
with effectiveness, productivity, safety, and satisfaction
in specified contexts of use.

4. Usability Test: Lab
http://www.sigchi.org/chi97/proceedings/overview/tst.htm
Usability Lab at Fidelity Investments

5. Watching Television – On-site

6. Scenario: Mobile Ticketing
1 Matti sees Madonna’s concert
promotion at bar in Tampere
He takes a picture of promotion
2 poster by using his mobile phone
Matti logs in to service for buying
3 tickets. Service identifies
Madonna’s concert proposition.
4 He buys the concert ticket and
travel ticket at the same time 6

7. …and the scenario continues
5 Mikko checks his route and
tickets through mobile phone
He validates travel ticket by
6 using a mobile phone when he
walks in to train at Tampere
Mikko decides to stop for one
7 beer and buy it by using mobile
phone
He validates concert ticket by
8 using mobile phone when he
arrives to gate of concert 7

8. Field Tests
(Tamminen & Oulasvirta 2005)

9. Testing for ”Quality in Use” Addresses
• Real users
• Real settings
• Real tasks
• Real events
• Real process
• Real details
• Real effects
• Real outcome
• Expected (quantitative) and unexpected (qualitative) issues

10. Usability Metrics: System Usability Scale
(SUS)
1. I think that I would like to use this system frequently.
2. I found the system unnecessarily complex.
3. I thought the system was easy to use.
4. I think that I would need the support of a technical person to be able
to use this system.
5. I found the various functions in this system were well integrated.
6. I thought there was too much inconsistency in this system.
7. I would imagine that most people would learn to use this system very
quickly.
8. I found the system very cumbersome to use.
9. I felt very confident using the system.
10. I needed to learn a lot of things before I could get going with this
system.
Sauro (2011)
http://www.measuringusability.com/sus.php

11. Processes for Managing Quality in Use:
Usability Maturity Model
• HCD1 Ensure HCD content in system strategy
• HCD2 Plan the HCD process
• HCD3 Specify user and organisational requirements
• HCD4 Understand and specify the context of use
• HCD5 Produce design solutions
• HCD6 Evaluate designs against requirements
• HCD7 Facilitate human-system implementation

12. Usability – Assuring Quality in Use
Marko Nieminen
Professor of Usability and User Interfaces, D.Sc.(Tech.)
Aalto University School of Science
Department of Computer Science and Engineering
SoberIT - Software Business and Engineering Laboratory