# The Human-Centredness Metric: Early Assessment of the Quality of Human-Centred Design Activities
## 2 Materials and Methods  
### Defining Human-Centredness in Context of Product Development  
In methodology research, forming classes and clusters of methods and approaches, as well as comparing and contrasting them, is a fundamental prerequisite for gaining insights. As shown in the Introduction, most authors define and distinguish between human-centred and non-human-centred methods depending on the user-designer interaction or whether some kind of user involvement is part of the method. However, this definition is difficult in exploring the added value that human-centred techniques have for product development. It is not possible to draw any clear conclusions about the extent of user involvement in the product design process on the basis of the naming of a method. Creativity methods such as paper prototyping or brainstorming, for example, can take place with strong user involvement or without any users at all. Are these particularly human-centred or not? There is also probably a difference in the quality of human-centredness depending on whether the product designers themselves have direct contact with end users or are merely presentedwith processed data from an interview study by an external consultancy firm. Nevertheless, in both cases, data are collected from users. On the other hand, simulations of operation situations without any involvement of real users can also provide valuable insights and improvements in terms of usability. Since we wish to measure human-centredness as a quality feature of a product design, defining it on the basis of user involvement is not practical. The ISO standards [8; 17], whose basic descriptions we follow, define human-centredness, on the one hand, on the basis of the four quality objectives: usability, accessibility, user experience, and the avoidance of use-related damage. These are better suited to our objective but would themselves need to be defined more precisely and distinguished from other synonyms, such as applicability and usefulness. On the other hand, the general human-centred development process [17] is also described here. It is characterised by the fact that the context of use should be understood and defined prior to the definition of the requirements. All further human-centred activities are based on the context of use. The context of use is an essential concept because it can be used to fully describe the context of every user-product interaction. It includes the user, his/her goals and the tasks that he/she pursues through the product interaction, the resources and equipment necessary, as well as the environment and situation of the interaction [17]. The context of use is therefore well suited to deriving a more wide-ranging definition that can be used to unambiguously identify human-centred activities as such. Figure 1 summarises the complete derivation of the definition for human-centred design. This will serve as the basis for deriving the metric and planning the experimental design. Human-centredness thus represents an overarching concept that can be projected at all levels of goal and action statements. On a very fundamental level, human-centred design can be described by its goal of making \"interactive systems more usable by focusing on the use of the system\" [8] and can be understood, according to an early definition by [PERSON] et al. [28], both as an overarching mindset and philosophy and as a specific design approach itself. Within the more specific scope of design research, we maintain this distinction at two different levels of abstraction and do not make any significant deviations in the definition at the level of the mindset (Figure 1, left).