Effectiveness is about the ability to create tools to author, reason about, and practically use a knowledge representation. Simple representations, such as first order logic are easy to reason about, but cannot express more complex concepts. Others, such as the richer forms of OWL may need human help or heuristics to verify.
Used in Chap. 2: pages 14, 16, 18, 19, 20
Used in glossary entries: heuristic evaluation function, knowledge representation, OWL