# The Human-Centredness Metric: Early Assessment of the Quality of Human-Centred Design Activities
## 1 Introduction
Not only does this brief snippet of research make obvious the different perceptions of human-centred design, but there is no agreement on which activities belong to human-centred design and which do not [9]. Looking at the current research on the topic of the assessment and measurement of human-centredness or user-centredness, it becomes clear that the evaluation of usability and the associated aspects, such as ergonomics, satisfaction, or efficiency, is already part of the human-centred development process itself [17]. There are therefore many standard works and reference books on the subject of assessing the usability or user experience of products, e.g., Ref. [18]. These measurement methods are usually--in line with the human-centred mindset--designed for a certain level of user interaction and therefore require functional and physical prototypes. However, there are also efforts to implement the evaluation of human-centred aspects even further upstream in the development process. One possibility is to create virtual rooms or 3D scenes instead of physical prototypes, to place the products to be tested in them virtually and then have them evaluated by users. [PERSON] et al. [19] evaluated the comfort of an aircraft interior design within a virtual reality setting. Virtual reality models were also used by [PERSON] et al. [20] to measure users' emotional responses while interacting with household appliances; in another work, the functional accessibility of indoor objects was assessed within 3D scenes [21]. Similarly, [PERSON] et al. [22] evaluated human factors within a VR set-up of a workplace. For such measurements, new assessment methods are sometimes developed or adapted, e.g., Refs. [21; 22; 23; 24]. In the search for measurement methods that can be used even earlier in the process, work can be found, for example, from the field of innovation research. For example, [PERSON] et al. [25] measured the originality and quality of concepts created by undergraduate students after carrying out a creativity method. [PERSON] et al. [26] compared the effect of two concept selection tools on the quality and novelty of the concepts within a student team project. [PERSON] et al. [27] evaluated the benefits of magic-based inspiration tools for the concepts of novice designers in terms of various objectives, including creativity, excitement, and enjoyment. According to them, the evaluation was carried out with prospective users, but they also specified that these were exclusively people with an engineering design background. The advantage of this type of measurement procedure and study design is that even a small change in the task for the participants--in this case, an additional design method--canbe measured and evaluated directly and immediately on the basis of its added value with regard to the achievement of the goal--in this case, an increase in innovation. Consequently, different design methods and their added value in terms of goal achievement can be compared with each other within an experiment. This is not possible yet within the context of human-centred methods and activities. Between the implementation of a method, e.g., a focus group, a prototyping workshop or a persona method, weeks and months can pass until the fulfilment of human-centred design goals, e.g., usability or user experience, can be proven with the help of established evaluation, e.g., with the use of prototypes. Many different factors apart from the methods may have influenced the design of the product in the meantime. No valid link can be derived between the methods and the product design, e.g., in the form of a measurement model, if a long time has passed between the input and the output to be measured. It is therefore also not possible to prove in such a setting that a specific human-centred activity had specific added value for the development of a user-friendly or accessible product.