Having walked through the Wheel of Science and given an overview of the process of science, we now turn to addressing some of the building blocks that help us move between theory and hypotheses to observation. Once our theories are formalized into testable hypotheses, we need to take a closer look at the variables including expanding on what variables are (versus constants), what we mean by “variance,” and how to operationalize variables and to recognize levels of measurement.


The primary task of social science is to explain the connection between concepts. We’ve explained that theory allows us to link concepts and that this theoretical pairing is formalized into hypotheses that state relationships between the concepts—how one concept impacts another concept (e.g., we expect that higher levels of education lead to higher levels of income). In order to test our hypotheses, we need to operationalize our concepts—finding indicators that measure concepts. Let’s revisit the relationship between education and income.


Operationalizing concepts simply means that we find variables (measures) of the concepts. If we are interested in operationalizing education and income, we could turn to a national survey (like we did in Chapter 1) and look for variables that measure “education” like “What is the highest level of education you have completed?” and “What was your total family income before taxes last year?” to measure “income.” These ...

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