Single-Principle Classification

NAICS is described as “unique among industry classifications in that it is constructed within a single conceptual framework.” Every boundary between industries demarcates differences in production processes, one principle, applied consistently.

Most classification systems implicitly mix multiple principles. An industry taxonomy might group some things by what they make, others by who they serve, and still others by technology used. This creates categories that look parallel but aren’t, comparing apples to oranges baked into the structure.

A single-principle system sacrifices some intuitive groupings in exchange for analytical coherence. When everything is classified the same way, comparisons across the system are meaningful. When principles are mixed, comparisons may be spurious even when they look legitimate.

The discipline required is to accept that some “obvious” groupings won’t exist because they would violate the organizing principle. The payoff is that the groupings that do exist can be trusted.

Related: 02-atom—supply-vs-demand-classification, 02-atom—classification-as-lens