Who are we missing? Self-selection bias in nonsuicidal self-injury research

Despite the threat of self-selection bias to the generalizability of research findings, remarkably little is known about who chooses to take part in non-suicidal self-injury (NSSI) research specifically. We aimed to establish the extent of willingness to take part in NSSI research within a commonly sampled population before assessing whether individual differences in demographic characteristics, NSSI lived experience, and participation experiences were associated with willingness to take part in future NSSI research.

New Zealand university students (n = 3098) completed self-report measures of their NSSI, psychological distress, emotional dysregulation, experience of their participation in the current study, and willingness to participate in future NSSI research.

Most participants (78.2%) indicated that they were willing to take part in future NSSI research. Men, older participants, people with NSSI lived experience, and those with more frequent past-year NSSI were more likely to be willing to take part in future NSSI research. Participants who reported a more positive subjective experience of the current study also indicated greater willingness.

Findings demonstrate systematic differences in who is willing to take part in NSSI research. Future research should implement methodological and statistical approaches to mitigate the impact of self-selection bias on NSSI research.