Substitutable causes in set-theoretic analysis resolve into a more abstract shared concept.

Evidence

To reconceptualize QCA results in this fashion, the analyst must identify the concept E for which C and D can substitute. Typically, this will involve moving up the ladder of abstraction to a more general concept. For example, Amenta and Poulsen (1996) show that there are two necessary conditions for New Deal policies such as OAA pensions, voting rights, and absence of patronage politics. To achieve sufficiency, some mechanism for positively pushing reform through government must be present. This can happen in substitutable ways, e.g., “administrative powers” or “democratic or third parties” (see also Amenta et al. 1992). These substitutable means are like variables C and D, while the general idea of a mechanism for achieving reform is like variable E. — Gary Goertz, Social Science Concepts, 1761

Categorization

• DEFINE: Explains the practical move of climbing the abstraction ladder so that substitutable conditions C and D collapse into a single more general variable E.
• XREF: Maps onto the necessary/sufficient condition structures for democracy discussed in chapter 1 — the same C-and-D substitution pattern underlies the New Deal and welfare-state cases.