Editing Operational definition (section)

=== Science ===
The [[theory of relativity|special theory of relativity]] can be viewed as the introduction of operational definitions for [[relativity of simultaneity|simultaneity of events]] and of [[length contraction|distance]], that is, as providing the operations needed to define these terms.<ref name=Woodhouse>{{cite book |title=Special relativity |author=NMJ Woodhouse |page=58 |url=https://books.google.com/books?id=ggPXQAeeRLgC&pg=PA50 |isbn=1-85233-426-6 |publisher=Springer |location=London |year=2003}}</ref>

In [[quantum mechanics]] the notion of operational definitions is closely related to the idea of [[observables]], that is, definitions based upon what can be measured.<ref name=Isham>{{cite book |title=Lectures on Quantum Theory |author= C. J. Isham |page=95 |url=https://books.google.com/books?id=xR3sS2hEFzcC&q=observable+operational+definition+quantum&pg=PA95|isbn=1-86094-001-3 |publisher=Imperial College Press |year=1995 }}</ref><ref name=Blank>{{cite book |title=Hilbert Space Operators in Quantum Physics |author1=Jiří Blank |author2=Pavel Exner |author3=Miloslav Havlíček |isbn=1-56396-142-3 |publisher=Springer |year=1994 |url=https://books.google.com/books?id=V0BSIoGXHLQC&q=observable+operational+definition+quantum&pg=PA252|page=252 }}</ref>

Operational definitions are often most challenging in the fields of [[psychology]] and [[psychiatry]], where intuitive concepts, such as [[intelligence (trait)|intelligence]] need to be operationally defined before they become amenable to scientific investigation, for example, through processes such as [[IQ test]]s.