A concept can be realized by multiple substitutable means across cases.

Evidence

Finally, I consider the substitutable relationship between the secondary and the basic levels. The secondary-level variables are neither causes nor constitutive features of the basic-level causal variables. Rather, each secondary-level variable is a substitutable means to a given basic-level variable. At the basic level is a concept such as “labor incorporation” (Collier and Collier 1991). Substitutability at the secondary level is an analysis of the different ways that labor can be or has been incorporated in different countries. In some countries this incorporation occurred via political parties, while in others it has been done by the state. — Gary Goertz, Social Science Concepts and Measurement, 1538

Categorization

• DEFINE: Defines substitutability: secondary-level variables as interchangeable routes to the same basic-level phenomenon.
• XREF: Labor incorporation via party versus state parallels classic comparative-politics typologies like Collier and Collier’s.