# What Are Measures and Metrics?

Measures and metrics are data tracking tools that allow you to see the status of various business elements. Choosing the best method for collecting your measures and metrics will depend on what information you are looking to get from them.

The extent, dimensions, quantity, capacity, etc., of something ascertained especially by comparison with a standard: to take the measure of.

## Units of Measurement

A unit of measurement is a definite magnitude of a quantity defined and adopted by convention or law. It acts as the norm for measurement of a particular kind of physical quantity, and it is possible to express any other value of that kind of quantity as a multiple of the measuring unit.

In science, a variety of uniform systems of units have been used, and many continue to be in use today. The most widely used is the International System of Units, which is also called the metric system, and is internationally agreed upon by scientists. The metric system is based on seven base units and 22 coherent derived units.

For convenience, the metric system also uses prefixes that increase or decrease by powers of 10, making it easier to convert between different units. A few non-metric units remain in widespread use, especially in the United States: for example, “gallons” rather than “liters” are used to describe volume at grocery stores and aircraft altitude is reported in nautical miles instead of feet.

## Measurement Theory

The philosophy of measurement encompasses a wide range of conceptual, metaphysical and epistemological issues that have been argued about for centuries. Some of these issues are discipline-specific while others are more general. Measurement theory is concerned with the conditions under which relationships among numbers and other mathematical entities can be used to express relations between real objects.

Mathematical theories of measurement have been developed by a variety of scholars, including operations theorists and conventionalists. Realists, however, have been critical of these theories.

They have interpreted the axioms of measurement as describing properties of concrete objects rather than observable relations between them. As a result, they have asserted that the precise true values of most physical quantities are unknowable unless derived from a chain of comparisons that traces back to primary measurement standards. They have also questioned why convergence among inaccurate measurements should be taken as evidence of truth. Instead, they have argued that the coherence criterion is a more appropriate standard for assessing the quality of measurement outcomes.

## Measurement Instruments

In practice, measurement experts use instruments to compare dimensions of objects with a preset pattern. This is what enables them to come up with the number that logically shows the relationship between the object and the template. Examples of measurement instruments include rulers, flexometers and gauges. Other instruments are used to verify that the result of a measurement falls within certain limits. These are called verifiers.

The signal produced by a measurement instrument can be displayed, recorded or used as input to some other device or system. The dynamic characteristics of the instrument are important for this task.

A good dynamic characteristic is linearity which means that the output reading of the instrument is proportional to the quantity being measured. The speed of response is another critical dynamic characteristic. This is the time from the moment the sensor ‘S’ receives the physical signal until the measurement is indicated on the display. This is normally expressed in terms of a percentage of the full scale reading.

## Measurement Applications

Measurement leads to numbers, which makes it an important part of arithmetic and statistics. It is also central to design and assembly, where it links to geometry. At work, measurement often seems to be more of a science than mathematics. For example, a lab technician might determine the concentration of potassium in water by using a spectrophotometer, which sends light through the liquid and measures the extinction (disappearance) of this light at different wavelengths.

All measurement systems require input conversion devices to convert the desired input to a number, and readout conversion devices to present this number. There are modifying and interfering inputs, which can change the outcome of a desired measurement in unintended ways. A method for correcting these modifying and interfering inputs is necessary in order to make the measurements precise. The most common purposes for which people use measurement at work are quality, monitoring, making something fit and safety. The results of these measurements are often reported as descriptive measures.

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