Test-retest reliability of the test of nonverbal intelligence (TONI)

Test-retest reliability of the Test of Nonverbal Intelligence (TONI) was investigated. Fifty students randomly selected from first and second grades were administered Form A and Form B of the TONI on two occasions 3 weeks apart. Test-retest correlation coefficients were calculated for all 50 subjects. The results showed high test-retest reliability: Correlation coefficients were .89 (Form A) and .83 (Form B). Parallel form reliability was also high: Form A correlated with Form B .88 on the first administration and .86 on the second administration.