Error - Science and Engineering

Science and Engineering

In statistics, an error (or residual) is not a "mistake" but rather a difference between a computed, estimated, or measured value and the accepted true, specified, or theoretically correct value. See also observational error.

In science and engineering in general an error is defined as a difference between the desired and actual performance or behavior of a system or object. This definition is the basis of operation for many types of Control systems, in which error is defined as the difference between a set point and the process value. An example of this would be the thermostat in a home heating system—the operation of the heating equipment is controlled by the difference (the error) between the thermostat setting and the sensed air temperature. Another approach is related to considering a scientific hypothesis as true or false, giving birth to two types or errors: Type 1 and Type 2. The first one is when a true hypothesis is considered false, while the second is the reverse (a false one is considered true).

Engineers seek to design devices, machines and systems and in such a way as to mitigate or preferably avoid the effects of error, whether unintentional or not. Such errors in a system can be latent design errors that may go unnoticed for years, until the right set of circumstances arises that cause them to become active. Other errors in engineered systems can arise due to human error, which includes cognitive bias. Human factors engineering is often applied to designs in an attempt to minimize this type of error by making systems more forgiving or error-tolerant.

(In computational mechanics, when solving a system such as Ax = b there is a distinction between the "error" — the inaccuracy in x — and residual—the inaccuracy in Ax.)