# Benchmark

The base or reference value is a numerical value, refer to the other values (eg measurements ) so that they can be expressed as the difference (deviation ) or as a multiple of the reference value. Conversely, the reference value may also be used for normalizing a value. At least two reference values or a reference value with an associated scattering interval to define a reference range.

A second meaning of the term is the unit with which all measurements of a size to be compared (see dimension), or units of a coordinate system and all metric scales.

## Reference values of measurements

For measurements of the reference value, a zero point or the starting point of a measurement is often (see also start value and zero measurement). In many cases, the mean value of a variable is used as reference; is held liable, the arithmetic mean, the names of the deviations of the individual values measurement error or measurement error. ( the geometric, the harmonic or the root mean square chosen as the reference, the variations thereof are named differently depending on the subject area ).

## Subject-specific reference values or reference values

In various fields, the term reference value is defined in a special way, or it is replaced by an entire reference system of many individual reference values .

For a review on the reference values of individual disciplines:

- Reference value ( acoustic ), depending on the unit
- Reference voltage in the audio equipment and the low-frequency communication equipment
- Reference value ( power) in the high-frequency technology
- Reference value in Medicine: In medicine, reference values of body functions, and biochemical analyzes provide guidance whether measured values are to be regarded as pathological
- In surveying the "mean figure of the earth in 1980 " in the form of the reference system GRS80
- In astronomy, for example, the polar star as a reference value of the brightness ( "2.0 like ").

Additional references:

- Of a derivative financial instrument in the form of currency or securities underlying value, see Underlying
- The calculated economic value analysis for the purchase price of a product, taking into account the volume-related price differences