In the application and implementation of usability and UX, the human being is in the foreground. EN ISO 9241-210:2020-03 describes this as a human-centred design. This design aims to make interactive systems more usable and focus on the use of the system.
Before the implementation of the individual steps, complete planning of the design process is required. The planning must define suitable methods to be used in the design process. Possible methods are Online questionnaires, interviews, personas, prototyping and wireframing, and user experience design. Surveys and interviews provide requirements for the redesign. While questionnaires generally address a broader mass and have large user numbers, interviews, on the other hand, provide in-depth information about the emotions and underlying feelings about a product. The terms persona, prototyping and wireframing are very often considered in the design process. To avoid redundancy, these are considered in more detail in the third activity in the design process. User Experience Design is a new method that puts the user more in the foreground. This method is critical when a system is being revised. Such a development has a high usage by users as its primary goal.
In addition to the methods mentioned, procedures should be defined that integrate this design process into other areas of system development and define users' exchange to the design process. In addition, persons responsible for the process should be identified. With the help of suitable milestones, the progress of the integration of this process can be recorded. If changes occur, these must also be taken into account in a timetable. The design process must be part of the overall project plan.
Fig. 1 illustrates the design process. The planning of the process has been given the number one here.
Once these aspects have been taken into account in planning, the actual design process can begin. According to ISO 9241-210:2020-03, four activities are necessary to design a human-centred system. These are labelled A to D in Figure 1. First, the context of use must be understood and described(A). User characteristics, tasks and environment of the system are factors on which information should be collected. For example, personas can be used here. A persona serves to determine the average user of the new application. Here, the person's previous knowledge, needs and wishes are written down. A persona can then be used to facilitate user-centred work. The entries in the persona are customisable and should be maintained. With the help of this information, the context of the design can be determined. For example, during a redesign, parts of the current context may remain, while other areas need to be completely reworked. According to ISO 9241-210:2020-03, the context of use description must identify users and stakeholders and record their characteristics. In addition, the goals and tasks of the users must be recorded, and the system environment must be described. A questionnaire can be written to obtain this information, for example, which asks the users about their context of use.
The next activity in the design process is the definition of the user requirements (B). This is the activity that should unify the previously defined context of use with the system goals. The user requirements must include the context of use as well as the requirements for the system. Also, there are usability requirements that were previously defined in the planning of the goals. Such requirements must also be defined in the context of use. Finally, some requirements directly influence the user and can be derived from organisational requirements. If conflicts arise in user requirements, they should be resolved as quickly as possible through compromise. Usage requirements should be verifiable, free of contradictions and kept up to date. They should also be verifiable by stakeholders.
The third activity in the design process of human-centred systems is elaborating design options (C). To evaluate different design options, different design solutions must first be developed. Such solutions can be developed with the help of user tasks, user-system interaction and user interfaces.
These first solutions are called wireframes because they only show the placement of elements on a page and represent the first layout. Also, the functionality is placed in the foreground in this step to concentrate on details later. Wireframes are often roughly sketched to be able to adapt to changes quickly. Once these initial wireframes have been drafted, these design solutions can be presented with the help of mockups or prototypes. The mockup is the further development of a wireframe. Mockups represent the structure of a website in more detail. However, it is not possible to click on different elements. This is also where the colour palette of the website is defined. At this stage, users can already be asked for feedback. A prototype is a model that is used for evaluation and can be adapted quickly and easily. The prototype is, therefore, the final design phase. In a prototype, elements can be clicked, and corresponding interactions can be carried out. With the help of a prototype's design, it can be prevented that changes have to be made to the finished system. Consequently, a prototype prevents unnecessary costs. If there is no need for changes, the solutions are passed on to the persons responsible for implementation. There are further standards for implementing these design solutions, which will not be discussed in detail here.
The fourth and last activity in the design process is the evaluation of the design (D). The earlier an evaluation takes place in the different phases, the better understanding the users' requirements can be incorporated into the final design solution. User-oriented evaluation can help get new information about user requirements and give feedback about the design solution's advantages and disadvantages from the user's point of view. These two aspects help to optimise the design. Furthermore, user-oriented evaluation helps to assess whether user requirements have been met. This can be checked using the prescribed standards. Finally, this type of evaluation makes it possible to collect baseline data or compare different design alternatives. The user-centred evaluation should include allocating resources to quickly incorporate improvements, scheduling, running tests on the system, analysing the results and communicating the proposed solutions to the design team.
As shown in Figure 1, the process can be restarted at any stage. Using iterations, the design can always be improved. For example, uncertainties or problems may arise during the evaluation of the requirements. Consequently, it is possible to jump directly to the requirements elicitation phase and continue the process accordingly. Such iterations are repeated until the final design is defined.
Once all iterations have been completed, a solution must be chosen. This solution is both technically feasible and understandable, and intuitive from the user's point of view.