INST 381: Research Methods Fall 2010

The Comparative Method

While the comparative method is often thought of as unique to “comparative politics,” its principles are basic social science principles that apply to all manner of political science research questions.

There are three basic types of “comparative” studies: Single-case studies (one case) Comparative studies (few cases) Large-N studies (many cases)

Single-case studies are “comparative” if you are using concepts, variables, theories, or hypotheses that are “universal” (that is, they can be applied to other cases). This means that the results of your study will still “speak to” other cases and can inform researcher involved in studying other countries. Single-country studies often rely on qualitative analysis and attention to detail.

Comparative studies look at a few cases (as few as two, but not much more than five or six). These must be picked in one of two ways:

Most similar systems (MSS) Most different systems (MDS)

The purpose is to pick cases that allow you to isolate or “control” for other variables beyond those specified in your hypothesis. Like single-country studies, these often also use qualitative analysis, but will less attention to detail. Here you are not “describing” your cases (as you would in a single-country study), but “comparing” your cases. Unlike large-N studies, you should focus on only a few variables (and these will be much more “abstract”).

Some rules of thumb for picking comparative cases:Dependent variable How similar are cases? Explanation

Mos

t sim

ilar

sy

stem

Different Very similar In MSS you are trying to explain why two cases that are in most ways very similar have had different outcomes on some important (dependent) variable. Example: Why does the US not have a major socialist party, unlike Great Britain, Canada, or Australia?

Mos

t dif

fere

nt

syst

em

Similar Very different In MDS you are trying to explain why two cases that are in most ways very different have similar outcomes on some important (dependent) variable.Example: Why Spain, Brazil, and South Korea all become democratic in the 1980s?

Large-N studies are studies that involve a large number of cases. While these studies can cover more cases and are therefore more “universal” in scope, they suffer from a loss of detail on any case. Here, cases are reduced to a handful of variables (or “indicators”) and it is the variables that matter, not the cases. But you must also be sure that your cases are representative of the total population.