Understanding the context of use is the basic requirement of successful usability engineering. The methods and techniques for this are the central core competence of usability engineers. The documentation of the context of use analysis is carried out according to the standard per core task in so-called context scenarios. These are episodic descriptions of tasks of a person (e. g. the future user), including their context and execution in everyday work as well as the effects of execution and visions to overcome weak points.

If there is no other basis for the creation, executives will interview selected people as suitable in key question interviews. Task, organization and cognition requirements as well as dialogue or product requirements are determined by means of the key questions. These result from

• (natural) environment (equipment, working environment, room composition),
• different usage situations,
• organizational embedding,
• Utility constitution of the users, but also from
• risks associated with the tasks, etc.

Similar to development-accompanying prototyping, a distinction can be made between

• explorative usage context description to assess the usability relevance of the core task and to determine possible areas of application of the interactive system and
• evolutionary or refining usage context description for specific development.

Especially for the redesigned development of interactive systems as part of complex work systems, the exploratory compilation and rough recording of possible contexts of use is a helpful and forward-looking approach that can only be partially covered by interview techniques because there are no experiences in the unknown.

The definition of usability-relevant work tasks can be done using a simple risk classification. Only tasks rated as critical need to be included in the more in-depth considerations of usability engineering, which may save a lot of effort. This is where useContext comes in. The documented results can then be further refined. An important instrument of this refinement can be useProcessCheck.

Using a special method of process analysis it can make an important contribution to optimizing usability. In the work sessions, work tasks are arranged in a high order and as completely as possible are mapped, thus creating a complete task model. useProcessCheck can be used in a variety of ways, from a collection and rough structuring of work steps to the documentation of the individual interactions in the user interface. Also as a controlling or key figure tool for the process or application ripeness level.

The same technology can also be used as a process description tool for documenting work processes in accordance with quality standards (ISO 9001/14001). It was tested very successfully in the certification audit of a high-revenue company in the chemical industry. The special description of the process steps and tasks in useProcessMap can be used as a central part of a quality manual. Usability engineering for optimization of usability is not possible without analyzing the embedding of the work tasks in the company processes or computer-aided work processes.

Usage requirements are derived from the accompanying investigations in cooperation with the users. During the design process, the tasks derived from the context of use are varied with the associated requirements in order to find usable solutions. In contrast to a requirement or functional specification, these are dynamic and are formulated and documented by usability engineers. In this respect, usability engineering is part of requirement engineering. There are many tools for documenting requirements, into which usage requirements can also be integrated and, if necessary, should also be integrated.

The development of design solutions is very deliberately kept in the plural. It is absolutely necessary to approach the users with design alternatives that are adapted to the respective specific work task. Not only to find the best solution, but also to show the target group that they should not be presented with accomplished facts.

When creating the solutions, the principles of design according to DIN EN ISO 9241-110 must be observed: Suitability for the task, self descriptiveness, conformity with user expectations, conducive to learning, controllability, error tolerance, Suitability for individualization. Not yet adapted in part 210, the new version of part 110 conducive to learning through learnability, error tolerance against robustness against user errors and individualizability against user binding replaced. It's debatable if it's an improvement: User binding is an element of marketing and not of ergonomics. Error Tolerance would have been better replaced by Error Avoidance from an ergonomic point of view. Learnable is basically also a very badly designed application, if it is operable.

Card sorting is a welcome first step towards user participation, which is to be shown in principle. With this usability method, easy-to-understand and usable hierarchies of terms are developed and checked through group work with users and/or subject matter experts. Information architectures, workflows, menu structures and navigation paths coordinated in this way minimize the training period and massively increase acceptance.

useCardsort can be used in a variety of ways, from a collection and rough structuring of terms to the documentation of a structured hierarchy of given terms.

In addition to wording that users can understand, prototyping is essential for usability engineering. During prototyping, the different design approaches are examined, discussed and, if necessary, tried out by users. It is desirable that prototyping only begins after by means of context scenarios a common basic understanding of all stakeholders has been established and the target of the change process is clear to everyone.

A distinction is made in development-accompanying prototyping

• Exploratory prototyping to determine requirements and rough design drafts and
• Evolutionary prototyping for their iterative further development.

Prototyping has an enormous influence on project success:

• Prototypes illustrate selected aspects of the future system.
• Prototypes promote the understanding of still unclear job requirements and design features that are difficult to imagine.
• The design of the prototype depends on the usage problems to be solved, beautiful screen layouts with icons and colors are counterproductive.
• Prototyping specifically helps to identify and eliminate familiarization problems (not enduring usage problems).
• The participants in the prototyping must be prepared for the presentation of the prototype, e.g. through a joint workshop to set goals.
• Through participation, prototyping massively increases user motivation (Mayo effect), especially if they are involved early on.
• Decisions in the prototyping process must be based on consensus, design alternatives help in consensus building.

A prototype can have different forms: from paper and pencil (also on a clipboard) to Office presentation graphics to GUI or mockup builders. It has been shown that a prototype designed too well yields poorer results. You should stay with the simple tools for as long as possible, not just because of the speed. Practice has shown that users at their workplace, for example call centers, can often only open simple files, which is why more complex tools tend to fail. This is another reason why usePrototype was developed.

Central here is the particularly simple use, so that even less computer-affine people can work with it. Easy-to-understand and usable surface designs can also be developed and checked through online group sessions with users and/or experts. Based on a fully mapped action regulation (W. Hacker), the essential design requirements from the workplace and accessibility are also found with ready-made design proposals.

New user interface elements derived from the cognitive and work-psychological basics in combination with ergonomic control system can be found in usePrototype as offered user interface elements. They fulfil many aspects of self-descriptiveness, conformity to expectations, conducive to learning, controllability and error tolerance.

For the so-called user-centered evaluation, there are basically three principles of procedure with increasing effort available: inspection by experts, examination with users (usability tests) and long-term observation. The sometimes demanding implementation is another element of usabitity engineers' core competence. Different methods and techniques can be used in each case.

To evaluate the usability, the tasks and the requirements to ensure comparability/validity have to be defined. Ultimately, the users are observed during this software-ergonomic test during the execution and, if necessary, interviewed. Effectiveness is not guaranteed if someone cannot manage the task at hand. Difficulties, bottlenecks and misuse determine the reduction in the extent of efficiency. The survey allows conclusions to be drawn about satisfaction++ and acceptance.

Usability engineering in company work systems is fundamentally different from that in consumer applications.

• Work systems usually have a high degree of complexity in the applications and the completed work tasks, for example periods of tasks up to a week.
• Necessary accompanying functions such as reminders, releases and transfers etc. Users can be trained and often work long-term with the applications. They are familiar with the most after a certain time.Typical of this are:
  • Customizing of ERP systems such as SAP etc.
  • Specialized call center applications e.g. with insurance companies
  • GUIs of control rooms and monitoring systems etc.

Conversely, consumer applications usually have a complexity that is necessarily minimized for untrained users.

• Users would otherwise fail and/or change vendor (binding).
• The design is very much based on external standards.
• But they can be part of a higher worker process.