1.3. Scope of the study

The general aim of the study was to choose, develop and experiment with some evaluation methods applicable to product design and capable of facilitating ergonomics-related decision-making. User participation was aimed to be an essential part of the experimental evaluations. Sound and realistic ways to involve users in the design process were sought. The study results, the different EEE procedures, can be used in developing activities related to the design process at workplaces and by product manufacturers. The procedures applied should be, after the developments, more tailored and consistent for (1) developing better products as far as absolute user-match is concerned and (2) comparing new systems and products with those of competitors (relative user-match). The study aims to utilise both ergonomic and usability expertise. Fig. 6 shows the papers versus the methods used. All the papers except VII are reports of experiments on elderly subjects, but some of the patients involved in the videophone experiment (paper VII) were also elderly people. Subjective assessment, though based on real perception during trials, is predominantly involved in most of the experiments, including comparison of the values of objective variables. Subjective assessment was assumed to be quicker and easier to elicit and analyse, and it also has an important role in consumer choices. The step experiment (paper I) was about purely objective assessment. The main emphasis in this study was on user-centred design with usability trials. Objective measurements were also made with instruments. Diverse research-style user trials were combined and developed into practical industrial tests in evidence-based ways.