User-Centred Design Methodology

The user-centred design methodology is essential for developing successful user interfaces Wolfe and McCracken (2004). It is user centric, not data centric, involving users in the process as much as possible with the goal of creating an interface that meets user expectations. This may include such activities as inviting users to participate on the design team, asking users to try out the product and following up on their feedback. Wolfe and McCracken (2004) further argue that user-centred design is highly interdisciplinary, drawing on knowledge from diverse fields such as art, psychology, computer science, amongst others.

Cato (2001) outlined the benefits of user-centred design as:

• Increased usefulness: The more evidently useful a product is, the greater the acceptance and the greater the desire the user has to use it

• Increased Efficiency: Helps users work in the way they prefer so they can be effective and efficient, rather than being ineffective wrestling with a poorly designed user interface

• Improved Productivity: Because the user is more effective and efficient, concentrating on the job in hand rather than the user interface

• Fewer Errors: Much of human error can be the result of a badly designed user interface. Really understanding the way the user is aware of what they see, how they understand it and how they will act can significantly reduce human error.

• Reduced Training Time: Consistency, support and reinforcement in a user- sensitive manner can reduce learning and competency time.

• Improved Acceptance: A quickly accepted interface leads to a system the user will trust and enjoy using. Enjoyment reduces stress and reduces the chance of rejection.

User experience design has its roots in user-centred design, a philosophy that places the end user at the centre of all design activities. User-centred design and other related areas (such as human factors engineering, human-computer interaction, interaction design, usability engineering and so on) all seek to humanise our interaction with technology Sward (2006). Figure 3.5 shows the relationship between user-centred design and user experience design.

While user-centred design generally focuses on usability: graphics and other design elements serve to facilitate and enhance the end user’s interaction with a product or service, user experience design is a process that extends the user-centred philosophy to incorporate all aspects of the end user’s interaction—even those that might seem intangible.

3.14 Usability Goals

Usability is generally regarded as ensuring that interactive products are easy to learn, effective to use, and enjoyable from the user perspective (Norman, 1988; Cato, 2001;

Sharp et al., 2007). It involves optimising the interactions people have with interactive products to enable them carry out their activities at work, school, and in their everyday life Sharp et al. (2007). More specifically usability is broken down into the following goals in Table 3.1.

Usability Goals Usability Criteria

Effective to use Effectiveness

Efficient to use Efficieney

Safe to use Safety

Having good utility Utility

Easy to learn Leamability

Easy to remember how to use Memorability Table 3.1: Usability goals and criteria (Sharp et a l, 2007).

As well as couching usability goals in terms of specific questions, they are turned into usability criteria. These are specific objectives that enable the usability of a product to be assessed in terms of how it can improve (or not) user’s performance. Examples of

commonly used usability criteria are time to complete a task (efficiency), time to leam a task (leamability), and the manner of errors made when carrying out a given task over time (memorability).

Schneidermann (1998) defined five attributes of usability as:

• Leamability: The system should be easy to leam, so the user can quickly get some work done.

• Efficiency: Once users have teamed the system, they should be able to use it productively.

• Memorability: The system should be easy to remember, so the casual user is able to use the system again without having to releam everything.

• Errors: the system should have a low error rate, so the user feels they are making positive progress and are in control, and if they do make errors they should be able to recover from them easily. Catastrophic errors should not occur.

• Satisfaction: the system should be pleasant to use, so users are subjectively satisfied when using it

Cato (2001) suggested other key attributes as:

• Control: Users feel they are in control rather than the system controlling them.

• Skills: users feel that the system supports, supplements and enhances their skills and expertise- it has respect for the user.

• Privacy: The system helps users to protect information belonging to them or their clients.

The International Standards Organisation (ISO) model (ISO 9241) defines usability as measures of the following.

• Efficiency: The accuracy and completeness the user achieves with respect to the goals.

• Effectiveness: The user effort required to achieve the user and the domain goal.

• Satisfaction: The measure of user satisfaction on a number of attributes.

• Usefulness: The measure of the value the user places on the product.

Although, these can provide quantitative indicators of the extent to which productivity has increased, or how work, training, or learning, have been improved, they do not however address the overall quality of the user experience, which is where user experience goals come into play Sharp et al. (2007).