Most democracy concepts use necessary-and-sufficient structure while their measures use family resemblance.

Evidence

Hence we have the most common form of concept-measure inconsistency: a necessary and sufficient condition concept with an additive (or averaging) measure. … This chapter shows that in general most concepts of democracy use the necessary and sufficient condition theoretical structure, while most measures use the family resemblance strategy, which as we have seen is typified by addition or the logical OR.Thus in terms of conceptmeasure consistency they do poorly. — Gary Goertz, Social Science Concepts, 641

Categorization

• DEEPTHINKING: The core diagnosis of the book: the mismatch is not between concept and data but between two formal structures silently operating in the same research program.
• XREF: Connects to Sartori/Collier-style concept-stretching debates and to measurement-invariance critiques in comparative politics. — connects to: The family-resemblance insight undercuts deliberative democracy’s aim of rational consensus. — Chantal Mouffe, The Democratic Paradox, 336