UWI Usability Lab

Usability

The predominant focus is the application of usability practices in industrial and IT product development. Our main goals are to promote and facilitate the use of usability practices within TT industries through the provision of usability testing facilities, resources and services.

We have established Caribbean's best-equipped usability testing facility within which we can determine how usable products really are. Further, our experiences in the usability testing field enables us to offer a range of services including analysis, design, engineering and testing of industrial products and IT systems.

1 Usability

1.1 What is Usability?

Usability characterises ease of use. It is a broad heuristic that encompasses ease of learning, efficiency of use, efficient user error recovery, ease of recollection and subjective acceptance by its intended users.

1.1.1 Usability

The International Standards Organisation according to ISO9241-11 define usability as:

"the effectiveness, efficiency and satisfaction with which a specified set of users can achieve a specified set of tasks in a particular environment".

This definition suggests that a 'usable' system enables its users to perform their computer-related tasks accurately and comprehensively (effectiveness) and doing so with ease--of learning, use and recollection (efficiency)--while fulfilling their task-related requirements (satisfaction).

Usability characterises ease of use. It encompasses:

· Ease of learning

· Efficiency of use

· Efficient user error recovery

· Acceptance by users.

1.1.2 Why is Usability Important?

Haynes writes that the importance of a usable product lies in cost-justification. Indeed, the financial gains gained by having greater usability include:

· Increased user productivity

· Decreased user errors

· Decreased training costs

· Decreased employee turnover

· Decreased work place injuries and lost time

· Decreased implementation costs (due to the avoidance of late design changes)

· Increased sales

· Decreased maintenance and support costs.

In dollar figures, IBM states that:

"Industry data show that each dollar spent on user studies during product design saves $10 on problem fixes during product development, or $100 or more in rework after product release. Also, maintenance costs can be substantially reduced if user requirements are gathered at the beginning of a project. It's estimated that 80% of maintained costs are spent on unforeseen user requirements, while only 20% are due to bugs".

(Feature stories: In a complex world, easy hits the spot, IBM, 1999).

The importance of usability goes beyond cost-justification alone. It also influences the way people (employees, clients and users) view the organisation. In terms of public relations, this is an important facet. Embodying usability and the quality that is implied creates an image of a well organised, pragmatic and intelligent organisation.

1.1.3 Is Usability Quality?

Quality should be an inherent characteristic of any human-machine artifact. It is a characteristic that embodies factors such as correctness, reliability, efficiency, integrity, maintainability, flexibility, testability, portability, reusability, interoperability and usability (Vatanawood). All systems should incorporate these factors--unfortunately few do.

So does usability equate to quality? In a sense, yes, as usability represents each element within the context of the system in use. Usability is quality in use.

1.1.4 Usability Engineering

Usability engineering is a branch of systems engineering that emphasises the ease in which a person is able to use a system--the concept encompasses the ethic that if a system is easy to use then it will be more successful. Systems engineering is defined by the International Council on Systems Engineering:

Systems Engineering is an interdisciplinary approach and means to enable the realization of successful systems. It focuses on defining customer needs and required functionality early in the development cycle, documenting requirements, then proceeding with design synthesis and system validation while considering the complete problem:

1. Operations

2. Performance
3. Test
4. Manufacturing
5. Cost & Schedule
6. Training & Support
7. Disposal

Systems Engineering integrates all the disciplines and speciality groups into a team effort forming a structured development process that proceeds from concept to production to operation. Systems Engineering considers both the business and the technical needs of all customers with the goal of providing a quality product that meets the user needs.

Thus, we see that usability engineering encompasses incorporating technical ease of use into the areas of operations, performance, testing, manufacturing, costing and scheduling, training and support, and disposal through:

· Defining and documenting customer needs and required functionality (performing requirements development),

· Performing design synthesis (user-centered design), and

· Performing system validation (evaluation and testing)

for each of these areas, while taking into account the overall business situation (the larger context) that the system will be in.

1.1.5 What is a System?

Briefly, the types of systems that are describe here consist of four main elements:

1. Components, which describe the operating part of a system,

2. Attributes, which are the properties of the components,
3. Relationships, which are the links between the various system components, and
4. Users, who interact with the system components.

Usability engineering focuses on the fourth element, users, and how they interact with each other and the rest of the system.

1.1.6 Why do Systems Fail?

Systems fail for many number of reasons. Sometimes the system itself has too many errors and is not easy to use. Other times the system is easy to use, but doesn't meet the requirements of the actual users. Often it comes down to poor communication and project management.

Many systems fail because they focus on the machines, not the people that use them. Consequently, users find that these systems do not meet their requirements, are difficult to learn and use, are not intuitive and do not leave them satisfied with their results.

Some systems fail because there is poor communication between the members of the development team and the client organisation. Sometimes the communication is poor between the individual members within the development team itself.

It is important to have explicit system goals and objectives. These should be stated and understood by all the development team at the very outset of the project. It is also important to keep sight of these goals.

Sometimes system goals and objectives are not suitable to the goals and objectives of the client organisation. A system must enhance the organisation, it's structure and culture. Sometimes, too, the system goals and objectives are too complex while the basic needs of the organisation are not met.

1.2 Usability: Usability Tips

1. Understand your users. Understand who the user is and gaining an appreciation of any relevant characteristics. Understand the user's goals and objectives when using the system. Identify the current tools used, while identifying any relevant knowledge and experience. Identify the relevant environment. Appreciate the situations that commonly arise as part of the user's normal activities. Understand the user's requirements and preferences.

2. Aim to meet specific user goals and requirements. Your system should enable your users to meet their overall task and job requirements in a way that is effective and efficient.

3. Structure your interface and navigational design in a way that is intuitive to the users' goals, tasks and processes. Prioritise the users' tasks and associated actions so that those more commonly used are more easily accessible.

4. Make objects and controls obvious: leave no room for confusion. Make it obvious what each object is used for and how to use it.

5. Be consistent and replicate. This should enable users to quickly and more efficiently learn and use your system.

6. Keep your design simple, don't clutter and don't distract. Don't confuse or lose your users and don't 'force' your users to focus on areas of the screen that are not relevant.

7. Give your users feedback. Let them know what the system is doing and what is expected of them.

8. Work with your users, not against them. Listen to what they do or don't tell you, don't laugh at them and don't blame them for being stupid.

9. Test, test, test! Test throughout the whole development process. Test your cognitive design through to the completed product.

10. Communicate with the rest of the development team.

UWI Usability Lab Usability

Revised: 11 June 2008