Assessment terms beginning with Z

This is a measurement glossary, not a general HR glossary. It covers the vocabulary that appears the moment you open a score report or challenge a vendor's claim — reliability, validity, norms, cut scores, item statistics and fairness analysis — because that is the vocabulary buyers are handed without explanation and the one that decides whether a number can carry a decision.

• Z-score

  Also called Standard score, Standardised score

  A z-score expresses a raw score as the number of standard deviations it sits above or below the mean of its norm group. A z of 0 is exactly average and +1 is one standard deviation above. It is the common currency into which most other standard scores are converted.

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