1. Measurement I. Knowing a Good Measure When You See It. Conceptual and operational definitions of a variable An example: voter turnout in the U.S. Measurement error and validity

2. Conceptual Definitions - 1 A conceptual definition of a variable states precisely what you mean when you use a particular term. A society that “supports democracy” is one that emphasizes tolerance, trust, political activism, and Post-Materialist values, not just one that pays lip service to the ideals of democracy. -- Ronald Inglehart

3. Conceptual Definitions - 2 A good conceptual definition: Looks at how other scholars have defined a term, and goes with the consensus unless there is a good reason to deviate. Allows you to test the theory that you want to test. Is not circular (for example, does not say that support for democracy is when the public voices support for democratic values)

4. Operational Definitions An operational definition of a variable is a complete recipe for going out into the world and measuring a variable. It helps us make the leap from our subjective impressions to an objective measure. Like a recipe in any good cook book, a good operational definition can be followed by any other chef.

5. Operational Definitions To measure “support for democracy,” Inglehart uses the World Values/ European Values Survey from 1995-97 and 1999-2001 and looks at average levels of agreement with nine statements such as: “Is it good to have a strong leader who does not have to bother with parliament and elections?”

6. Voter Turnout in the U.S.: Measure 1 Conceptual: “Turnout” is the percentage of those who can vote who actually do. The traditional operational definition is: Where Voting Age Population (VAP) includes noncitizens and convicted felons, but not citizens living overseas.

7. Voter Turnout in the U.S.: Using Measure 1

8. Voter Turnout in the U.S.– Measure 2 Conceptual: “Turnout” is the percentage of those who can vote who actually do. Where Voting Eligible Population is purged of noncitizens and convicted felons but includes citizens living overseas.

9. Voter Turnout in the U.S.: Measures 1 and 2

10. Measurement Validity Measurement Validity is highest when the gap between your conceptual definition and your operational definition is smallest.

11. Measurement Error Measured Value = True Value + Bias + Random Error Sources of Bias: 1. “Response Bias:” survey respondents lie 2. Faulty instruments: scale is always off, question wording always bad.