Evaluation is usually understood as the assessment or appraisal of projects, processes and functional units (e.g. devices, objects) as well as organisational units: Organisational units. Context, structure, process, effort and result can be included. In general, evaluation can also be understood as the fundamental examination of whether and to what extent something appears suitable to fulfil an intended purpose. In linguistic usage, evaluation, investigation and analysis are also used synonymously in the sense of a stocktaking without a particular purpose orientation. Evaluation serves the retrospective control of effects, the forward-looking control and the understanding of situations and processes. The evaluation data can be used to adapt and optimise the processes under investigation.