1.1. Basics of user-centred product design

Traditionally, ergonomics has concentrated on developing human-machine systems. Simultaneously to this, however, it has also emphasised the importance to fit the task to the human (Kroemer & Grandjean 1997). Pheasant (1996) has concluded that the objective of ergonomics (human factors engineering) is to achieve the best possible match between the product and its users in the context of the (working) task that is to be performed (Fig. 1). The following criteria for successful match have been proposed: functional efficiency, ease of use, comfort, health and safety, quality of working life – and so on. In other words: ergonomics is the science of fitting the job to the worker and the product to the user. And there are an increasing number of products that involve the user in complex interactions (McClelland 1990).

The fact that it is possible to measure the interaction between the users and the products they use is the fundamental principle underlying all ergonomics (McClelland 1995). Ergonomics increases product value (Cross 1989). In this context of study, ergonomics can be described as an approach to design products in a user-centred way. If the user-product-task interaction is approached from the product design point of view, the product is the only component that can be manipulated (Keinonen 1996). Users act in a context and designers study this context of use. Generally, however, designers, such as the engineers of the manufacturing company, cannot influence the users, tasks or environments.

It has been emphasised by Tang (1991), for example, that the recent trends in design include understanding of the users’ needs and the context in which the users work or live, or even involving the users in the design or product development process (user participation). There should be ergonomic participation at both organisational and individual levels (Wilson 1994). Through participation, users may be able to influence the design of a new system in a way that satisfies their needs. They may thereby develop feelings of ownership. They may thus develop a better understanding of the new system and the ways in which it can help them in their jobs (Barki & Hartwick 1994). User participation will even generate a feeling among the workforce that the new system is an evolution of their own efforts and expertise, and this may result in greater acceptance and commitment in making the new operational practices work (Kontogiannis & Embrey 1997).

The components of the user-product-task interaction will be presented next. User is defined as an individual interacting with the system (ISO 9241-10 1996). In commercial or marketing terms, a user is a customer or a consumer. However, not all users are individual customers, as the customer can also be an organisation which chooses and buys the product for its employees, who thus act as end-users. Ehn and Löwgren (1997) have defined ‘user’ more widely:

• a representative person in the statistical or pragmatical sense;

• an individual person in a unique context;

• a person working in a collaborative setting;

• a component of a work system;

• an organisation;

• a stakeholder;

• an end-user;

• an organisation representing users;

• a customer.

In this study, users are understood as end-users. Users can comprise all people or citizens, or they can be various subgroups of the total population, identified according to age, gender or profession. Older people and people with reduced functional abilities have not been seen as a significant user group in mainstream product development (Hyppönen & Poulson 1999). Elderly people have, however, become an important consumer group. This is due to a combination of the shift in the demography of the population and an increase in the level of their personal disposable income. The rising health care costs and the increasing proportion of elderly people out of the total population make it vital to ensure the independence of the aged (Wheeler et al. 1985). At the very least, economic factors should increase the need for human factors/ergonomics input oriented towards older adults in the design of work, home, and leisure environments (Fisk 1999). This has important implications for designers: Can they cater to the needs of a population group they have no previous experience of (Rogers et al. 1997)?

Product is an artefact conceived, produced, transacted and used by people because of its properties and the functions it may perform (Roozenburg & Eekels 1995). Additionally, a product can be defined as stable, lasting and having no changing properties (Keinonen et al. 1998a). This complete definition differentiates products from prototypes, which are under development, and from systems, the installation of which involves further definitions. According to McClelland (1995), the term ‘product’ is meant to embrace:

• the physical attributes of traditional three-dimensional products, such as household appliances, vehicles, office equipment, medical apparatus, etc.

• the control/display systems ranging from simple ’knobs and dials’ to full software-based control systems found in information technology products

• the material required to support the use of a product, such as user instructions or help facilities.

Task is an everyday term linked with human work and daily activities. Work sciences, including ergonomics, utilise it generally. Preece et al. (1994) propose the following definition of task: ”a task can be defined as the activities required, used or believed to be necessary to achieve a goal using a particular device”. A task cannot be seen in isolation from the users and the environment (Draper 1993 in Carlshamre 1994). Task is defined by Stammers and Shepherd (1995) as follows:

• the term ‘task’ generally applies to a unit of activity within work situations,

• a task may be given to or imposed upon an individual or alternatively carried out on the individual’s own initiative and volition,

• it is a unit of activity requiring more than one simple physical or mental operation for its completion,

• it is often used with the connotation of an activity which is non-trivial or even onerous in nature,

• it has a defined objective.

Designing is the intellectual attempt to meet certain demands in the best possible way (Pahl & Beitz 1988). Roozenburg and Eekels (1995) have defined product design as the process of devising and laying down the plans that are needed for the manufacturing of a product. In ergonomics, design can be defined to be a process of creating a system or a product with functions to meet human beings’ needs (Hsiao 1998). In this process, some characteristics at the social, economic, technological, psychological, physical, anthropological, artistic and aesthetic levels should be considered such that the artificial environment or system can satisfy the psychological and physical demands of human beings. Therefore, the designer actually faces a holistic, contextual system of individual-technology-task-environment-organisation (Fig. 2), even though the designed object is only a small product. The system in Fig. 2 is an extension of that shown in Fig. 1.

According to McClelland (1990), the points defined for design processes concerning human - computer interaction (HCI) by Carroll and Rosson (1985) can be applied to any major product development activity. The points are:

• Design is a ”process”. It is neither a state nor an artefact that can be described as a static entity. It is a dynamic socio-technical activity.

• The design process involves both ”bottom-up” and ”top-down” approaches and often intense interaction between the two.

• The design process is ”radically transformational”, involving the development of interim or partial solutions, which may never be part of the final design.

• Designing to a particular set of goals almost always results in different goals emerging as the final design solution evolves.

The basis on which the product is built is the intended user and the tasks that the product can help the user to perform. The user may also be part of a participative design process by evaluating and testing the design proposals at different stages of development and even by acting as a domain area specialist in the design team (Preece et al. 1994). Pahl and Beitz (1988) have concluded that engineering product design is part of a more comprehensive process called “product development”.

The user-centred design approach is widely accepted as a successful way of designing interactive products and systems (Säde 1996). In the European Union, utilisation- and user-centred approaches have been strongly emphasised in product development processes. For instance, EU has proposed five phases to implement a telematic R&D project with close involvement of the users during each phase (Building… 1996). The phases are:

1. Study the needs of the users.

2. Translate their needs into functional specifications.

3. Build a demonstrator.

4. Validate the demonstrator with users in real-life situations.

5. Elaborate a plan for exploiting the results.

Demonstrator is a prototype application developed in a project for validation purposes. Project validation involves two important stages: (a) a verification stage, which uses a small but sufficient sample of users in a real-life situation to test the technical feasibly of the demonstrator and also yields preliminary findings on user acceptance, and (b) a demonstration stage, where a sufficiently large sample of users in a real-life situation provide information on cost-effectiveness, user-friendliness and similar issues, as well as testing the feasibility of the system when used on a large scale (Building… 1996).

User-centred design has also been emphasised in standards. Many standards of the Finnish standard organisation, SFS, in concordance with the common EU standardisation, suggest that users should be involved in the development process. One part of the ergonomic tasks to be performed during the design process is evaluation with operators (SFS-EN 614-1 1999): to use scale or full-size models of the work equipment or its parts, or simulators, to evaluate the design together with actual operators and to foresee probable activities. This should also include an evaluation of any documentation.

User-centred design can be started by, for example, conducting a user study. An effective user study is an important basic tool for preventing mismatch and, hence, for promoting usability. Ergonomic usability studies help to elaborate the concepts initiated through a requirement analysis supported by user studies (Fig. 3) (Väyrynen et al. 1999). Incorporating human factor research and testing into the product development process improves product usability and quality (Cushman & Rosenberg 1991). This enhances, among others, the product’s chances for success and greatly reduces the likelihood of legal action against the product’s manufacturer. Additionally, ergonomic requirements are part of the comprehensive set of safety criteria for machinery stipulated in the EU directives, which are enforced in Finland by the Finnish Council of State, and can be fulfilled by applying corresponding EN standards (e.g., SFS-Handbook 93-4 1999).

There are many examples of cost savings obtainable by applying user-centred design methods. Early detection of problems helps to minimise the amount of time, effort, and costs associated with making design changes (Cushman & Rosenberg 1991). According to Nielsen (1993), subsequent requests for improvements will be about 100 times more expensive than the implementation of change in the early phases of product development. In addition, early test results provide an indication of the likelihood of user rejection of the product while there is still time to make modifications. If you do not test your system for usability, your customers will do that, while struggling to use it. Knowledge of the problems encountered will spread around and undermine your reputation.