Measurement enables us to make statements about a measured parameter in relation to a unit of measurement. A measurement is always based on several factors. These include:
- The measurement principle, which sets out the scientific requirements for the measurement. A parameter can only be measured (quantified) if there is a measurement principle. There are also many non-physical parameters such as volume levels that can be attributed to measurable physical parameters (in the case of volume level this would be acoustic pressure, for example).
- The measurement method, which describes how a measurement is carried out (e.g. via zero balance or differential measurement).
- The measurement procedure, which is when the measurement principle and method are implemented in a practical application.
Measurements are taken using measuring tools or equipment (such as scales, thermometers). External factors that could influence the result need to be taken into account. The objects of measurement can be physical bodies, activities or states. A distinction is made between direct measurements (that can be read directly) and indirect measurements (that need to be derived).