Operational definitions are descriptions of the observations and measurements of the people/objects/events relevant to the term or phrase being defined.

One operational question inre: operational definitions, is this: What do people/objects/events do when they  _____ [term/phrase being defined operationally]?

Operational definitions thus function as operational answers to operational questions.

Examples:

Operational Question: What do people do when they do philosophy?
Operational Answer: When people do philosophy they create concepts and principles which describe people, objects and events and they develop techniques for using those concepts and principles.

Operational Question: What do people do when they love?
Operational Answer: When people do love they say they like each other and they do good deeds for and with each other.

Operational definitions can be created using structured sentences such as the following:

_____ [Term/phrase being defined operationally] IS _____ [Description of the people/objects/events relevant to the term/phrase being defined].

Example: The mind [Term being defined operationally] IS an individual’s personal system of desires/fears/priorities as evidenced by his observable actions and reactions, in particular, as evidenced by his approach behavior to  people/objects/events he desires and his avoidance behavior from people/objects/events he fears [Descriptions of the observable/measurable people/objects/events--in this case the events of approach/avoidance--relevant to the term being defined].

_____ [Term/phrase being defined operationally] IS WHEN _____ [Description of the people/objects/events relevant to the term/phrase being defined].

Example: Love [Term being defined operationally] IS WHEN someone says they like you and they do nice things for you and with you [Description of the people/objects/events relevant to the term being defined].

IF _____ [Description of the people/objects/events relevant to the term/phrase being defined],
THEN _____ [Term/phrase being defined operationally].

Example: IF someone says he likes you and does nice things for you and with you [Description of the people/objects/events relevant to the term being defined],
THEN that is love [Term being defined operationally].

WHEN _____ [Description of the people/objects/events relevant to the term/phrase being defined],
THEN _____ [Term/phrase being defined operationally].

Example: WHEN someone says he likes you and does nice things for you and with you [Description of the people/objects/events relevant to the term being defined],
THEN that is love [Term being defined operationally].

By operational definitions, abstract concepts/principles can be defined by the descriptions of real-world people/objects/events; thus, by operational definitions, abstract concepts/principles/techniques can be made concrete/made into concrete concepts/principles/techniques.

If a person cannot provide a description by means of the observation(s)/measurement(s) of the people/objects/events related to a term he wishes to define/use in a discusssion, then there is an excellent chance that (A) the people/objects/events he is trying to define/discuss do not exist or (B) he does not know what he is talking about.

Operational definitions are required for The Code of Science [http://www.bobkwebsite.com/thecodeofscience.html] to ensure that scientists can communicate with each other and with nonscientists.

Notes:

[1] Stanovich, Keith
How To Think Straight About Psychology
Scott, Foresman and Company, Glenview, IL, 1989

“... In short, the explanation of phenomena, not the analysis of language, is the goal of the scientist. The key to progress in all the sciences has been to abandon essentialism and to adopt operationalism ... . [p. 39.]

Where ... does the meaning of concepts in science come from if not from discussions about language? What are the criteria for the appropriate usage of a scientific concept? To answer these questions, we must discuss operationism, an idea that is crucial for the construction of theory in science, and one that is especially important for evaluating theoretical claims in psychology.” [p. 39.]

“Although there are different forms of operationism, it is most useful ... to think of it in the most general way. Operationism is simply the idea the concepts in scientific theories must in some way be grounded in, or linked to, observable events that can be measured. Linking the concept to an observable event is the operational definition of a concept and makes the concept public. The operational definition removes the concept from the feelings and intuitions of a particular individual and allows it to be tested by anyone who can carry out the measurable operations.” [p. 39.]

“The link between concepts and observable operations can vary greatly in [the] degree of directness or indirectness. Some scientific concepts are defined almost entirely by observable operations in the real world. [Other] concepts [are] defined only partially by these direct links. ...[The] use of some concepts is determined by both a set of operations and the particular concept’s relationship to other theoretical constructs. [There] are concepts that are not directly defined by observable operations but are linked to other concepts that are. These have only an indirect operational definition, one that comes from other concepts that are defined more directly by observable operations.” [p. 40.]

“Thus, although theoretical concepts differ in how closely they are linked to observations, all concepts acquire their meaning partially through their link to such observations, a point emphasized by noted Harvard philosopher W. V. Quine: ‘The sentences of science, no matter how theoretical, acquire what meaning they have through a network of sentence-to-sentence links whose starting point is sensory stimulation. All evidence for the truth of a scientific theory, moreover, is drawn from sensory observation through the same network.’ (1985, p. 32.) In short, operationism, not debate about language, determines the meaning of concepts in science.” [p. 40.]

“[Operationism] is not unique to psychology. It is characteristic of all sciences. ... This is what makes possible the public nature of science, one of its defining features. Two different scientists agree on the same operational definition so that is possible for one to replicate the other’s results.” [p. 43.]

Calvin S. Hall and Gardner Lindzey.
Introduction to Theories of Personality.
John Wiley & Sons, New York, NY, 1985.

Empirical definitions, or as they are often called, operational definitions, attempt to specify operations that we can use to measure relevant variables. It is by means of these definitions that the theory comes in[to] contact with observational data, or the real world. [p. 7.]

Alan O. Ross.
Personality: The Scientific Study of Complex Human Behavior.
Holt, Rinehart and Winston, Inc., 111 Fifth Avenue, New York, NY 10003, 1987.

[A] scientific theory must [provide] definitions of its terms. These definitions permit us to move from the abstractions of the theory to the research-based data we must have in order to test the predictions that the theory generates. Definitions of this kind are like a dictionary that enables us to translate theory language into data language. [Emphasis in original.] [p. 26]

The way to move from theory language to data language is to provide operational definitions for each of the terms in the theory. [p. 27]

[2] Greene, Brian
The Elegant Universe
Vintage Books, Random House, Inc. New York, 2000
p. 249.

The most meaningful definitions in physics are those that are operational—that is, definitions that provide a means, at least in principle, for measuring whatever is being defined. After all, no matter how abstract a concept is, having an operational definition allows us to boil down its meaning to an experimental procedure for measuring its value.

[3] Greene, Brian
The Elegant Universe
Vintage Books, Random House, Inc. New York, 2000
p. 203

"The physicist Ernest Rutherford once said, in essence, that if you can't explain a result in simple, nontechnical terms, then you really don't understand it. He wasn't saying that this means your result is wrong; rather, he was saying that it means you do not fully understand its origin, meaning, or implications."

[4] Bernstein, Jeremy
Einstein
Penguin Books, 625 Madison Avenue, New York, NY 10022, USA, 1976.
p. 35.

There is one thing I would be glad to ask you. When a mathematician engaged in investigating physical actions and results has arrived at his conclusions may they not be expressed in common language as fully, clearly, and definitely as in mathematical formulae? If so, would it not be a great boon to such as I to express them so?--translating them out of the hieroglyphics, that we might also work upon them by experiment. I think it must be so, because I have always found that you could convey to me a perfectly clear idea of your conclusions, which, though they may give me no full understanding of the steps of your process, give me the results neither above nor below the truth, and so clear in character that I can think and work from them. If this be possible, would it not be a good thing if mathematicians, working on these subjects, were to give us the results in this popular, working state, as well as in that which is their own and proper to them? -- Michael Faraday, age 66, to James Clerk Maxwell, age 26, inre Maxwell's use of mathematics to describe electromagnetics.

Cited in MacDonald, D.K.C., Faraday, Maxwell and Kelvin, p. 79.