Test standardisation: reliability, validity, norms

Standardisation turns a collection of items into a test whose scores mean the same thing whoever takes it. A reliable test gives consistent results, a valid test measures what it claims to measure, and norms tell us what a raw score means by comparison with a reference group. For example, a raw score of 40 is meaningless until norms show whether most comparable candidates scored above or below it. This chapter explains how each of these three pillars is established and checked.