CF Dictionary · Decision Making

Category (of a factor)

A discrete group on a continuous spectrum, defined by breakpoints. CF uses categories to convert analog factors to digital ones.

A category is a discrete group on a continuous spectrum, defined by breakpoints. "Baby", "child", "teenager", "adult" are categories on the age spectrum.

Categories vs. continuous values

  • Continuous. Real-valued: "they're 13.7 years old."
  • Categorical. Discrete: "they're a teenager."
  • Mixed. Some breakpoints preserved, others continuous.

CF prefers few categories (2–5) where possible:

  • 2 categories is binary (pass-fail).
  • 3–5 categories captures common conceptual distinctions.
  • Many categories is effectively analog — look for hidden breakpoints.

Defining categories

  1. Conceptual. "Is this category conceptually meaningful?"
  2. Breakpoint-based. "Is there a real breakpoint between this and the next?"
  3. Goal-relevant. "Does the distinction matter for our goal?"

Categories and margins

When you put a value in a category, the margin of the breakpoint determines borderline cases. Standard policy: round borderline cases down (or up, but pick a rule and apply consistently).

"If a factor uses 2-5 discrete categories then it's often already like the result of finding 1-4 breakpoints for an analog factor." — criticalfallibilism.com