Work out cognitive test scaled score instantly with clear inputs, formula shown and shareable results.
Wechsler subtest scaled scores use a mean of 10 and standard deviation of 3, so scaled = 10 + 3z against age-group norms. A raw score of 34 where the age group averages 28 with SD 5 gives z = 1.2 and a scaled score of 13.6 - above average, at the 88.5th percentile. Age norming is essential because raw ability changes with development.
Scaled score
scaled = 10 + 3 x z, using age-group norms
Interpretation bands
8-12 average, 13-15 above average, 16+ very superior
Because raw cognitive performance changes sharply with age. A ten year old's raw score means something different from an adult's.
Because 19 is three standard deviations above the mean, beyond which the norming sample contains too few cases to differentiate reliably.