Control cases should be chosen where the outcome nearly occurred.

Evidence

For example, Skocpol chooses as her control cases events such as Russia 1905 or Prussia 1848 where it seems that social revolution“might have occurred.” Chapter 7 uses the Possibility Principle to construct the complete set of negative cases within the scope of Skocpol’s theory of social revolution. — Gary Goertz, Social Science Concepts, 171

Categorization

• XREF: Connects to the broader literature on case selection and Mill’s methods, and to how historical counterfactuals are licensed.