Political Science 30: Political Inquiry

1. Political Science 30:Political Inquiry

2. Qualitative Research Design II • Selecting on the Dependent Variable • Mills’ Method of Agreement • Mills’ Method of Difference • Examples • Clem Miller • Dreze and Sen

3. Selecting on the Dependent Variable • Selecting cases according to the value of the dependent variable that they take on is more controversial than selecting on the independent variable. • It allows you to look at extreme values or divergent cases. • “However, if this design is to lead to meaningful … causal inferences, it is crucial to select observations without regard to values of the explanatory variables. K.K.V.”

4. Selecting on the Dependent Variable: Method of Agreement • When you use Mills’ Method of Agreement, you select cases that take on the same values of the dependent variable. • This helps you to rule out possible causes, because independent variables that vary over these cases can’t cause the dependent var. • This method can only disprove a hypothesis, because it can’t find a correlation.

5. Selecting on the Dependent Variable: Method of Agreement This design could help us rule out “early industrialization” as a cause of whether a country has a viable socialist party.

6. Selecting on the Dependent Variable: Method of Difference • When you use Mills’ Method of Difference, you select cases that take on different values of the dependent variable. • After you have selected your cases, you determine what values they take on for some independent variables. • Perhaps one independent variable will vary across your cases, and explain the D.V.

7. Selecting on the Dependent Variable: Method of Difference Adding a country that has no viable socialist party can add causal leverage to our early investigation.

8. Example: Clem Miller • This Congressman writing home to his supporters tells the story of two different lobbying efforts on behalf of farmers. • Let’s assume that his process of case selection came in the same order that his narrative is written. • If so, he selected on independent variables and used the “Most Similar Systems” design.

9. Example: Clem Miller

10. Example: Dreze and Sen • Both countries began a new political regime at mid-century with large populations and little wealth. • They have diverged since then: “There is little doubt that as far a morbidity, mortality, and longevity are concerned, China has a large and decisive lead over India. (p. 205)” • “What has brought about that lead is a matter of very considerable interest. (p. 206)”

11. Comparing Many Research Methods: Measurement Validity • Measurement validity judges the gap between your conceptual definition and your operational definition. • Qualitative – Highest measurement validity • The measurement validity of other research methods (Lab experiments, quasi/natural experiments, and quantitative research) really depends on what you are trying to measure.

12. Comparing Many Research Methods: Internal Validity • Internal validity judges how well a research design has tested a causal relationship, in the cases examined. Random assignment is the key. • Lab Experiments – highest • Quasi/Natural experiments – medium • Qualitative research – medium • Quantitative research – lowest

13. Comparing Many Research Methods: External Validity • External validity is how confident we can be that a causal relationship identified in our cases can be generalized to the outside world. Random sampling is key • Quantitative research – highest • Quasi/Natural experiments – medium • Lab experiments – low • Qualitative research – low

14. Comparing Many Research Methods: Overall Lessons • The best research design depends on your research question and the particular problems that it poses. • The best research uses a mixture of methods to test a hypothesis.