Qualitative Research Design II

 Selecting on the Dependent Variable  Mills’ Method of Agreement  Mills’ Method of Difference  Examples  Clem Miller  Dreze and Sen

 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.”

 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.

CaseEarly Industrialization? Viable Socialist Party? FranceNoYes BritainYes 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.

 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.

CaseEarly Indust.?Feudalism?Viable Social Party? FranceNoYes BritainYes USAYesNo 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.

 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.

CaseEconomic Trouble? Sympathy of Officials? Well Organized? Govt. Help? Walnut Growers Poultry Men

 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)”

 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.

 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

 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

 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.