Embedded performance validity tests (PVTs), like Digit Span PVTs from Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV), offer a valuable means of evaluating validity without extending administration time. This study investigated the utility of novel indices of performance inconsistency for WAIS-IV Digit Span (DS IRs) in the detection of invalid performance among 705 adults referred for ADHD evaluation. Results showed DS IR indices were inadequate in classifying overall validity status (areas under the curve = 0.52-0.59). Predictably, four established Digit Span PVTs effectively distinguished between valid and invalid performance score groups (areas under the curve = 0.74-0.78) with 32-49% sensitivity and 86-93% specificity at optimal cut-scores. Overall, individuals with noncredible performance scores did not differ significantly from those with valid scores regarding performance inconsistency on WAIS-IV Digit Span.