The rapid naming subtest is a measure of Rapid Automatic Naming (RAN). RAN is a strong predictor of literacy development. Those that are slower at naming items are at higher risk for reading/literacy difficulties and dyslexia.
The score is based on the time it takes to correctly name the items on the screen.
Only the colours or letters that the child reads out loud correctly during the time limit are counted as correct, therefore any that are missed would be entered as incorrect along with any wrong answers.