The ability of the Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A; J. N. Butcher et al., 1992) validity scales to detect random, partially random, and nonrandom MMPI-A protocols was investigated. Investigations included the Variable Response Inconsistency scale (VRIN), F, several potentially useful new F and VRIN subscales, and formulas F-sub-2 - F-sub-1 and F + F-sub-2 + |F - F-sub-2|. Protocols completed by 150 adolescents at a juvenile court setting, screened for randomness with a matched-pair Millon Adolescent Clinical Inventory (MACI) or Jesness Inventory, were compared with 100 computer-generated, all-random protocols, and with 5 levels of partially random protocols. VRIN was the most effective scale in detecting all-random protocols; however, the optimum cutoff of [greater than or equal to] 75 failed to identify 1/3 of them. Using the new scales, a decision algorithm was described that correctly classified 94%-95% of protocols as interpretable, partially interpretable, or uninterpretable.