Usability as quality of use

According to part 11 titled ‘Guidance on Usability’ of the ISO 9241 standard (1998), usability is 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 is a standard covering a number of aspects for people working with computers. Currently titled ‘Ergonomic requirements for office work with visual display terminals (VDT), it will be available as ‘Ergonomics of Human System Interaction’ in the near future.

Usability as a software quality

Part 1 of ISO/IEC 9126 (1992) defines Usability as one of the six characteristics to describe software quality as:

A set of attributes of software which bear on the effort needed for use and on the individual assessment of such use by a stated or implied set of users.

ISO/IEC 9126 is superseded since 2005 by ISO/IEC 25000, the latest being ISO/IEC TR 25021:2007, ‘Software engineering- Software product Quality Requirements and Evaluation (SQuaRE)- Quality measure elements’.

Brief Description of the Walkthrough Process

The Cognitive Walkthrough has the same basic organization and rationale as other types of design walkthrough, such as requirements walkthroughs and code walkthroughs (Yourdon, 1989). It is a review process in which the author of one aspect of a design presents a proposed design to a group of peers. The peers then evaluate the solution using criteria appropriate to the design issues.

In the Cognitive Walkthrough, the reviewers evaluate a proposed interface in the context of one or more specific user tasks. The input to a Walkthrough session includes an interface’s detailed design description (perhaps in the form of a paper mockup or a working prototype), a task scenario, explicit assumptions about the user population and the context of use, and a sequence of actions that a user should successfully perform to complete the designated task.

Overview of the Cognitive Walkthrough Process

1. Define inputs to the walkthrough
   1. Who the users are
   2. Sample tasks for evaluation
   3. Action sequences for completing the tasks
   4. Description or implementation of the interface
2. Convene the analysts
3. Walk through the action sequences for each task
   1. Tell a credible story, considering…
      1. Will the user try to achieve right effect?
      2. Will the user notice that the correct action is available?
      3. Will the user associate the correct action with the effect they are trying to achieve?
      4. If the correct action is performed, will the user see that progress is being made toward soluition of their task?
4. Record Critical Information
   1. User knowledge requirements
   2. Assumptions about the user population
   3. Notes about side issues and design changes
   4. The credible success story
5. Define inputs to the walkthrough

During the Walkthrough process the group considers, in sequence, each of the user actions needed to accomplish the task. For each action, the analysts try to tell a story about a typical user’s interaction with the interface. They ask what the user would be trying to do at this point and what actions the interface makes available. If the interface design is a good one, the user’s internetions should cause him or her to select the appropriate action. Following the action, the interface should present clear feedback indicating that progress is being made toward completing the task.

An augmented-reality system merges the real scene viewed by the user with computer-generated virtual objects to generate a composite view for the user. The virtual objects supplement the real scene with additional and useful information. Sounds may be added through the use of special headphones that allow the user to hear both real sounds and synthesized sounds. There are also special gloves that a user can wear that provide tactile sensation such as hardness or smoothness. A user wearing such gloves could “feel” virtual furniture in a real room. In an augmented-reality system, users can walk around a real room, hear the echo of their footsteps, and feel the breeze from an air conditioning unit, while at the same time they can see computer-generated images of furniture or paintings.

One of the requirements of an augmented-reality system is that it needs to be interactive in real time. Animation, sound, and textures are added in real time so that what the user sees, hears, and feels reflects the true status of the real world. The most important characteristic of augmented reality is the ability to render objects in three-dimensional space, which makes them much more realistic in the eyes of the user.Virtual objects are drawn in relationship to the real objects around them, both in terms of position and size. If a virtual object is situated partially behind a real object (or vice versa) then the user should not see part of the obscured object.Occlusion of objects is the largest contributor to human depth perception.

The major difference between augmented reality and virtual reality is that in virtual reality everything that is sensed by the user is computer generated. Therefore the virtual objects must be rendered as photorealistically as possible in order to achieve the feeling of immersion. Augmented reality uses both real and synthetic sights, sounds, and touches to convey the desired scene, so virtual objects do not bear the entire burden of persuading the user that the scene is real, and therefore they do not need to be so photorealistic. Augmented reality lies in the middle of the continuum between absolute reality (in which everything sensed is real) and virtual reality (in which everything that is sensed is created).

One of the world’s leading experts on choice, Sheena Iyengar talks about fundamental differences in how the idea of choice differs across different countries and cultures. Citing various interesting examples from her research spanning a more than 15 years, she explains the assumptions which inform the American view of choice and how too much choice can impose constraints instead of opportunities.

About Sheena Iyengar

Sheena Iyengar is one of the world’s leading experts on choice. Iyengar’s research has been informing business and consumer-goods marketing since the 1990s. Her experiments have provided experiments have provided rich material for Malcolm Gladwell and other pop chroniclers of business and the human psyche.

Sheena teaches courses at the Columbia Business School to MBAs, Executive MBAs, and Executives, including courses at the World Economics Forum in Geneva, Switzerland. Her work is regularly cited in top news outlets such as The New York Times, the Wall Street Journal, and on National Public Radio.

Related Links

Sheena Iyengar’s website

Sheen Iyengar on Facebook

Sheena Iyengar on Twitter

The Art of Choosing (buy book from Flipkart) | The Art of Choosing (buy book from Amazon) | The Art of Choosing (buy audio book/ CD from Amazon)

John Underkoffler starts of by talking about how, around twenty five years ago, the Macintosh fundamentally changed the way people thought about computation, computers and how they used them, and that it was such a radical change that the early Macintosh development team had to write an entirely new OS from ground up for it. Referring to the advancement in fundamental supporting technologies, he talks about how one can buy more graphic power in less than a 100 dollars, and that same power would cost a million bucks from SGI a decade ago.

He goes on to demo a few projects of his and the ‘g-speak spatial operating environment’, as he call it and ends by saying that in five years time from now, when you buy a computer, this will very much be part of what you will get with it.

About John Underkoffler

John Underkoffler owns Oblong Industries, a company he founded to move the g-speak spatial operating system into the real world. Oblong is building apps for aerospace, bioinformatics, video editing and more.

Before founding Oblong, Underkoffler spent 15 years at MIT’s Media Laboratory, working in holography, animation and visualization techniques, and building the I/O Bulb and Luminous Room Systems.

Related Links

Oblong Industries
g-speak: Minority Report Gesture based User Interface now Reality

Ergonomics (or Human Factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance.

Ergonomists contribute to the design and evaluation of tasks, jobs, products, environments and systems in order to make them compatible with the needs, abilities and limitations of people.

A person’s perceptions and responses that result from the use or anticipated use of a product, system or service.

Nielsen Norman Group’s defintion for User Experience

“User experience” encompasses all aspects of the end-user’s interaction with the company, its services, and its products. The first requirement for an exemplary user experience is to meet the exact needs of the customer, without fuss or bother. Next comes simplicity and elegance that produce products that are a joy to own, a joy to use. True user experience goes far beyond giving customers what they say they want, or providing checklist features. In order to achieve high-quality user experience in a company’s offerings there must be a seamless merging of the services of multiple disciplines, including engineering, marketing, graphical and industrial design, and interface design.

1. Drag a rectangle from the widgets pane to the stage/ wireframe pane.
   
2. Drag a second rectangle from the widgets pane to the wireframe pane.
   
3. Right-click the second rectangle, select ‘Edit button shape’ and then ‘Rounded Top’ from the context menu.
   
4. The rectangle will now appear as the image below.
   
5. Snap-align the bottom edge of the ‘Rounded Top’ rectangle to the top edge of the rectangle below.
   
6. Resize the second rectangle to the size of a tab.
   
7. Copy and paste the tab (or click the tab, hold ‘Ctrl’ on the keyboard, and drag the tab) you just created and align it horizontally to the right of the first tab.
   
8. Right-click the duplicated tab and select ‘Order’ and then ‘Send Backward (or use the shortcut ctrl+[) till the second tab goes behind the first rectangle.
   
9. You’re done. You should now have one active and one inactive tab as appears in the image below.
   

If you want create a vertical tabbed menu, then choose ‘Rounded Left’ in place of ‘Rounded Top’ in step 3.

Rob Tanen begins to talk about how user researchers have historically lacked appropriate technology for studying how people use technology and the emergence of a variety of tools that can be applied to data gathering, analysis and sharing. He talks about the need for awareness and guidance in the selection and use of such research technologies.

Tanen goes on to talk about the basic characteristics of effective user research tools: documentation, measurement, efficiency and enhancement, data on current usage of various technologies for data gathering, analysis and presentation, demonstrations and tips on the latest technological tools for conducting user research, including high-speed digital video and pen computing and concept designs of future user research tools.

About Rob Tanen

Rob Tanen is Director of Research at Bresslergroup, a product design and development firm. Rob has over 15 years experience applying product/interface usability in the medical, industrial, commercial and consumer fields.

Rob is creator and editor of DesigningforHumans, the Industrial Designers Society of America (IDSA) blog focusing on events, methods and technology related to user research. Rob has a BA in Cognitive Science from Vassar College, and MA and PhD degrees in Human Factors/Experimental Psychology from the University of Cincinnati.

Related Links

Designing for Humans
Bresslergroup

David Kelley, chairman of IDEO, says product design has become more about the user experience than about hardware. He shows a video of this new, broader approach, including footage from the Prada store in New York.

About David Kelly

David Kelly is the founder of IDEO. He helped design the first mouse, the Treo and the Leap chair. Kelley has also been teaching design at Stanford for more than 25 years and now leads the university’s design school there.