An accurate, comprehensive insight into how a product is used by its users in practice (the so- called use practice) is essential for designing products that meet user expectations. A user centred approach in product development processes asks for a deeper understanding of user characteristics related to the (unexpected) problems users face when interacting with particular products and services.
User characteristics and product properties are a useful source of information that help designers to foster such a understanding of target users and the product in development. When designing for a specific user group, the ‘user characteristics’ helps you to better understand the target group and predict usability problems in practice.When designing for ‘all’, the ‘product properties’ helps you anticipate usability problems of your next generation products at the start of the product development process.
Usability refers to specific users, performing a specific task, with a specific product in a specific context (Eason, 1984; Shackel, 1991; Nielsen, 1993). In addition , subjective satisfaction is a crucial dimension to define the concept of usability (Lauesen & Younesi, 1998; Han et al., 2001; Babber et al., 2002). In analogy to soft reliability problems (Koca et al., 2008), soft usability problems are problems in which the most important issue is that users are unsatisfied about the quality of the interaction. Although the behaviour of users is one of the factors to play an important role in usability, the diversity in behaviour when interacting with products has only recently become serious object of study. In a globalizing market, a ‘design for all’ policy does not seem to work well, and local needs and demands appear to be increasingly important. These individual demands are not only shown between cultures or countries but also in subcultures or specific groups of people who share some characteristics or behaviour (De Leur et al., 2006; Kim et al., 2006; Rodriguez et al., 2006; Leventhal & Barnes, 2007). As a result, the development of products to satisfy diverse users has become more and more challenging thanks to the demands of user characteristics.
To design products that satisfy their target users, a deeper understanding is needed of their user characteristics and product properties in development related to unexpected problems users face. These user characteristics encompass cognitive aspect, personality, demographics, and use behaviour. The product properties represent operational transparency, interaction density, product importance, frequency of use and so on. This study focuses on how user characteristics and product properties can influence whether soft usability problems occur, and if so, which types. The study will lead to an interaction model that provides an overview of the interaction between user characteristics, product properties, and soft usability problems.
Method and results
In total three surveys and one experiment were conducted. The first survey was a questionnaire survey to explore what usability problems users experienced in the Netherlands and South Korea. This study resulted in the categorization of soft usability problems. The second survey investigated how user characteristics are related to the occurrence of specific soft usability problems. Finally, an experiment was conducted to find out how user characteristics are correlated to specific soft usability problems depending on type of product in the USA, South Korea and the Netherlands. Based on the findings from the studies, an interaction model (PIP model: Product-Interaction-Persona model) were developed which provides insight into the interaction between user characteristics, product properties, and soft usability problems. Based on this PIP model a workshop and an interactive tool were developed. Companies can use the PIP model to gain insights into probable usability problems of a product they are developing and the characteristics of those who would have problems using the product.
The PIP model was validated in the companies involved in the project to see how it is used in the product development process and what should be improved. The validation also included workshops in which designers in the companies could experience and learn how the findings and the model and the tool are applicable to their design process.
A card set provides the definitions of three categories of soft usability problems with examples in actual use and retrospective evaluation, and can be found on the Results page.