What feature of a psychometric test should discriminate as widely as possible across the variety of human response?

• A. Discriminatory power
• B. Validity
• C. Reliability
• D. Norms

Answer: (A)

Discriminatory power is what you want a psychometric test to maximize. It reflects an item's ability to differentiate between people who differ on the trait being measured. When discriminatory power is high, individuals with higher levels of the trait tend to score differently from those with lower levels, producing a clear separation in overall scores. This broad spread is what lets the test detect subtle differences across the variety of human responses.

Validity, reliability, and norms are important aspects of a test’s overall quality, but they address different things. Validity asks whether the test measures what it’s supposed to measure; reliability is about consistency of scores; norms describe how scores are distributed in a reference group. The feature that directly governs how well the test separates people across the trait spectrum is discriminatory power.