Performance invalidity in traumatic brain injury litigants with poor quality of education: a South African cross-cultural study

<b>Introduction:</b> Performance invalidity is under-studied in countries outside of the United States of America (US), with non-English examinees and with those who have low levels or poor quality of education.<b>Method:</b> This cross-cultural neuropsychological study explored performance invalidity in South African adult traumatic brain injury (TBI) litigants (N = 100) who had 7‒12 years of poor quality of education and who spoke Afrikaans (n = 35), English (n = 9) or one of the indigenous African languages of Xhosa (n = 52), Swahili (n = 1), Pedi (n = 1), Sotho (n = 1) and Chichewa (n = 1) as first languages.<b>Results:</b> Using demographically appropriate cutoff scores for seven performance validity tests (PVTs), the prevalence of performance invalidity was calculated as being close to 30% for this group. Participants who failed zero or one PVT were categorized as performing validly, while those who failed ≥ 2 PVTs were categorized as performing invalidly, raising suspicion of feigned cognitive impairment. Only 9% of the participants failed three or more PVTs. Severity of brain injury and the demographic factors of age and level of education did not play a significant role in PVT failure.<b>Conclusion:</b> Considering the prevalence rate and that South African psychologists now have access to PVTs with demographically appropriated cutoff scores, South African psychologists no longer have an excuse not to include PVTs in their test batteries, even with examinees who have severe TBI.