The potential for linking cohort participants to official criminal records: a pilot study using the Avon Longitudinal...

Introduction: Linking longitudinal cohort resources with police-recorded records of criminal activity has the potential to inform public health style approaches and may reduce potential sources of bias from self-reported criminal data collected by cohort studies. A pilot linkage to police records in the Avon Longitudinal Study of Parents and Children (ALSPAC) allows us to consider the acceptability of this linkage, its utility as a data resource, differences in self-reported crime according to consent status for data linkage, and the appropriate governance mechanism to support such a linkage. Methods: We carried out a pilot study that linked data from the ALSPAC birth cohort to Ministry of Justice (MoJ) records on criminal cautions and convictions. This pilot was conducted on a fully anonymous basis, meaning we cannot link the identified records to any participant or the wider information within the dataset. Using ALSPAC data, we used summary statistics to investigate differences in self-reported criminal activity according to socio-economic background and consent status. We used MoJ records to identify the geographic and temporal concentration of criminality in the ALSPAC cohort. Results: We found that the linkage appears acceptable to participants (4% of the sample opted out), levels of criminality are high enough to support research and that the majority of crimes occurred in Avon & Somerset (the policing area local to ALSPAC). Both those who opted out of linkage or did not respond to consent requests had higher levels of self-reported criminal behaviour compared to participants who provided explicit consent. Conclusions: These findings suggest that data linkage in ALSPAC provides opportunities to study criminal behaviour and that linked individual-level records can provide robust research in the area. Our findings also suggest the potential for bias when only using samples that have explicitly consented to data linkage, highlighting the limitations of opt-in consent strategies.