Operational Definitions

Psy 5054 ]


Brian Linzie's Hints for Writing Operational Definitions

Operationism:   The definition of terms by the operations used to attain them (from Christensen, 1985).

The principle of operational definition was originally set forth by Bridgman (1927) and was incorporated into psychology shortly thereafter. Operationism means that terms must be defined by the steps or operations used to measure them. Such definition is necessary to eliminate confusion in communication. Consider the statement "Hunger causes one to perceive food-related objects selectively." One might ask, "What is meant by hunger?" Stating that hunger refers to being starved only adds to the confusion. However, stating that hunger refers to eight hours of food deprivation communicates a clear idea. Now others realize what hunger means and can, if they so desire, generate the same degree of hunger. Setting down an operational definition forces one to identify the empirical references, and so ambiguity is minimized.

An operational definition is a "recipe" (set of procedures) for creating an independent variable or measuring a dependent variable. Think of a cooking recipe: the recipe tells you what tools to use (measuring cup, wire whisk), and how long certain operations are carried out (mix until smooth). It does not say whether the measuring cups need to be plastic, glass or tin--as long as it is a standard measure it will give the correct output. If they don't specify time as a way to stop a process (stir for 2 minutes) they specify some other detail to look for (until lumps disappear).

Operational definitions are used to avoid confusion about the meaning of concepts. Clear operational definitions also allow others to replicate your results. If you can explain how you created your IVs and measured your DVs clearly enough for others to replicate the procedure, then there is no confusion about how you define the concepts you are studying.

Some Guidelines for Writing Operational Definitions On Psy 5054 Exams:

  • If the IV is created with an apparatus (e.g., a computer, a tachistoscope, a stack of index cards) be sure to say what the apparatus is.
  • If the concept is an IV, tell what the researcher did to create the levels. If, "test word spelling" was an IV, there may be two levels: (1) correct spelling = normal English spelling found in Merriam Webster's Collegiate Dictionary (10th Edition), and (2) incorrect spelling = transpose two letters to create a spelling not found in Merriam Webster's Collegiate Dictionary (10th Edition).
  • If the DV is measured with an apparatus (e.g., an eyetracker, a computer keyboard, a tape recorder) be sure to say what the apparatus is.
  • If the DV includes a measure of time, be sure to include the units (e.g., msecs, seconds).
  • Be sure to say how the participants responded to the stimuli (e.g., eyemovements, voice reaction time, press a button, recall a story) .
  • If your operational definition is taken from a research article, include about as much detail as was included in the article.
  • If your operational definition is taken from a research article, don't assume I (as the grader) have read the article--this is an exam and you need to tell me what you know.
 

Psy 5054 ]

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This page was last updated on 11/08/99.