Political Science 30: Political Inquiry

1. Political Science 30:Political Inquiry

2. Qualitative Research Design I • Qualitative vs. Quantitative Research • Two types of observational study • Nonrandom case selection • Selecting Cases on the Independent Variable • Most similar systems • Most different systems • Income Inequality and Civil War

3. Qualitative vs. Quantitative Research • Qualitative and quantitative studies are both types of observational studies. • Quantitative research measures differences in number for variables, and usually studies a large number of cases (Large “N”). • Qualitative research measures differences in kind for variables, and usually studies a small number of cases (Small “N”).

4. Qualitative vs. Quantitative Research • Because it covers a broad range of cases, quantitative research yields conclusions that can be generalized (it has the strongest external validity). • Because it looks closely at a few cases and traces causal pathways, qualitative research outperforms quantitative research in its measurement validity and internal validity.

5. Qualitative vs. Quantitative Research • When selecting cases for your quantitative research sample, it is imperative that you use random selection. • In qualitative research, “selection must be done in an intentional fashion, consistent with research objectives and strategy.” (King, Keohane, and Verba, 1994, p.139)

6. Selecting Cases on the Independent Variable • “Selecting on the independent variable” means “selecting your cases according to the values of the independent variable that they take on.” • In order to do this, you have to know a little bit about all of your potential cases. • In order to do this right, you cannot act as if you also know the values that the dependent variable takes on.

7. Selecting Cases on the Independent Variable • The Most Similar Systems method selects cases that take on similar values of confounding variables, but different values of a key independent variable. • This “holds constant” the confounds because they take on the same values in all of the cases. • This is the design recommended by King, Keohane, and Verba.

8. Selecting Cases on the Independent Variable • The cases that you might select in a Most Similar Systems design will differ based on the research question you ask. • USA, Canada, and Britain in a study of life expectancy. • Bill Clinton, Jimmy Carter, and JFK in a study of regional appeal in voting. • Genghis Kahn, Hannibal, and Hitler in a study of how to defend invasions.

9. Selecting Cases on the Independent Variable • The Most Different Systems method selects cases that take on very different values for multiple independent variables. • If it turns out that these cases all take on the same value of a dependent variable, then we can rule out the independent variables as causes of the dependent variable. • Less useful since it can only disprove a hypothesis.

10. Income Inequality and Civil War Income Inequality Poverty Civil War Colonial Past External Threat

11. Income Inequality and Civil War

12. Income Inequality and Civil War • We can hold the confounds constant by selecting these similar cases from Latin America. • It appears that income inequality does lead to civil war.