Calling a feature essential implies conjunctive aggregation, not averaging

Evidence

Notice that Polity talks about “essential” and “interdependent elements” between these constitutive features of democracy. This terminology means using the logical AND, and conversely that the mean or sum is not appropriate. — Gary Goertz, Social Science Concepts and Measurement, 290

Categorization

• DEFINE: Translates qualitative conceptualization language (‘essential,’ ‘interdependent’) into a formal aggregation rule — logical AND versus mean/sum.
• XREF: Connects to measurement-validity debates in any index-building literature — e.g., composite governance or democracy indices that average subcomponents that are conceptually conjunctive.