Open to interpretation? Inconsistent reporting of lifetime nonsuicidal self-injury across two common assessments

Nonsuicidal self-injury (NSSI) is typically assessed using either single-item questionnaires or checklists of common behaviors, but preliminary research suggests that checklists produce higher lifetime prevalence rates. In 2 preregistered studies (combined n = 1,364), we tested whether memory cueing afforded by behavioral checklists accounts for this discrepancy. Participants reported their lifetime NSSI history using both a single-item and a checklist, with presentation order randomized across participants. Nearly a third of participants reported inconsistent NSSI histories on the 2 assessments, with participants 1.57 times more likely to report an NSSI history on a checklist than on a single-item. Counter to the memory account, this discrepancy was evident even when participants completed the checklist first, suggesting that the increased prevalence estimates captured by checklists are unlikely to simply reflect memory facilitation. Across the 2 samples, 12.5% of participants would have been incorrectly screened out in 2-step assessments; these participants were more likely to have engaged in NSSI historically, less likely to self-injure by cutting, and (in Study 2 only) were more likely to be men. These studies suggest that the inconsistencies across 2 of the most common NSSI assessments arise because people dissimilar to the lay conceptualization of self-injury are less likely to endorse a single-item, even when they have affirmed engaging in self-injury behaviors on a checklist. We argue that single-item and checklist assessments capture different aspects of NSSI, such that future research should distinguish between behaviorally identified NSSI assessed with behavioral checklists and self-identified NSSI assessed with single-item assessments. (PsycInfo Database Record (c) 2020 APA, all rights reserved).