Operational Definitions

Goal: Understand the role of operational definitions in psychological research

Objective 1:

Differentiate operational definitions from those that appear in dictionaries.

Benchmark 1.1:

State, in general terms, the difference between definitions that appear in dictionaries and operational definitions.

Benchmark 1.2:

Given an example, say whether or not it is an operational definition.

Benchmark 1.3:

Give at least two examples, one original, of operational definitions of psychological concepts.

Objective 2:

Present and discuss two ways in which operational definitions improve communication in psychological research.

Benchmark 2.1:

State how operational definitions assist the participants in a single research project.

Benchmark 2.2:

Explain why operational definitions can improve the reliability of observations in research.

Benchmark 2.3:

Say how operational definitions are helpful to researchers attempting to replicate or extend someone else’s research.

Objective 3:

Describe potential problems associated with the use of operational definitions in psychological research.

Benchmark 3.1

State and give a brief explanation of each of the two main problems associated with the use of operational definitions.

Benchmark 3.2

Given a description of several consequences, identify those which can result from the use of operational definitions.

In psychological research, our task involves making measurements that describe, usually quantitatively, how individuals or groups react in a particular situation.  The specific procedures used in making these measurements must be indicated, both for those carrying out the research project initially and, later, for those reading about the results.

If you think about the types of questions which interest psychologists, you will begin to understand why very precise, detailed descriptions of measurement techniques are necessary.   Psychologists often study characteristics of individuals and actions that cannot be measured by instruments.  How happy is someone?  How persistent?  How angry?  In conducting research on these and other abstract concepts, researchers use operational definitions.

An operational definition is different from one you find in a dictionary.  It explains, for a given concept in a specific research situation, how that concept is to be measured.  Take the example of someone’s level of happiness.  We might, in a research project, have an operational definition of happiness based on the individual’s score on a ten-item questionnaire about their happiness level.   Alternatively, our operational definition might rely on observations of the percentage of time, in a ten-minute interval, that the subject was smiling.  In either case, we have provided a description of an observable procedure that we followed in measuring an abstract characteristic of an individual.

Operational definitions are important communication tools in psychological research.  First, because there often are several people involved in the collection of data in a research project, operational definitions help them focus on the same information, the same features of a behavioral event.  Thus, measurements made using good operational definitions are more likely to be reliable.  Second, operational definitions assist other researchers in following the same procedures used in the original study, as they attempt to replicate or build upon the first research.

Of course, there are sometimes problems associated with the use of operational definitions.  Because they are specific to one or a few research projects, each psychologist is free to create their own operational definition of a concept, if they don’t like those used by others.  This becomes a problem if, using very different measurement approaches for the same concept, researchers ultimately draw quite different conclusions.  These conclusions may not reflect any genuine differences in the concept of interest, but may just be a result of the measurement procedures.

A second potential problem arises if an operational definition doesn’t connect to the underlying concept in a logical way.  Suppose a psychologist creates an operational definition of “happiness” which relies on a count of the number of jokes someone tells in a certain time period.  The researcher claims that the happier a person is, the more jokes they tell.  We might legitimately argue against such an operational definition, citing the many happy people we know who, in spite of being happy, don’t tell jokes often.  In this case, we are pointing to other kinds of evidence to suggest that frequency of joke telling isn’t a very good operational definition of happiness.

In spite of possible problems, the use of operational definitions is generally a useful strategy in conducting psychological research.  Good operational definitions can make the research process more efficient and also can improve the accuracy of communication about the research to others.