Fred Kerlinger's definitions

Scientific research is a systematic, controlled, empirical, and critical investigation of hypothetical propositions about the presumed relations among natural phenomena

Theory: a set of interrelated constructs (concepts), definitions, and propositions that present a systematic view of phenomena by specifying relations among variables, with the purpose of explaining and predicting the phenomena.

Hypothesis: a tentative proposition about the relation between two or more phenomena or variables. 

Concept: Expresses an abstraction, e.g., "achievement."

Construct: a concept which is invented or adopted for a special scientific purpose, e.g., "intelligence."

Constitutive definition: defines a construct with other constructs, e.g. "weight" by saying that it is "heaviness."

Operational definition: assigns meaning to a construct or a variable by specifying the activities or "operations" necessary to measure it.

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1. What is the difference between a concept and construct? Give two personnel-related psychological examples.
2. How does a constitutive definition differ from an operational definition? Give a work -related example.
3. Provide an operational definition for performance that is binary and one that is polytomous.
4. How does a true independent variable (IV) differ from a subject variable? Give an example of each.
5. How can age be defined operationally as a trichotomous or a linear variable?
6. Identify a moderator variable that could influence the relationship between worker performance and motivation level

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