T-score

A standardized score with a mean of 50 and a standard deviation of 10, commonly used in psychological testing.

A T-score is a standardized score with a mean of 50 and a standard deviation of 10. T-scores express how far a person's raw score sits from the norm group's mean, in standard deviation units, on a scale that's intentionally easy to read: a T-score of 60 is one standard deviation above average; a T-score of 70 is two.

T-scores are common in clinical assessment because they avoid the negative numbers and decimals that come with raw Z-scores while preserving the same statistical information. Many clinical instruments flag T-scores of 65 or 70 as worth further investigation.

Z-score — A standardized score expressing how many standard deviations a raw score is from the mean.
Norms — Reference distributions of scores from a defined population, used to interpret an individual's score in context.
Standardization — Administering, scoring, and interpreting an assessment under uniform conditions, with reference norms from a defined sample.
Percentile rank — The percentage of scores in a reference group that fall at or below a given score.
Normal distribution — A symmetric, bell-shaped probability distribution that describes how many psychological traits are spread across a population.

T-score

Related terms