Mohler, G.Mishra, S.Ray, B.Magee, L.Huynh, P.Canada, M.O’Donnell, D.Flaxman, S.2022-07-142022-07-142021-06Mohler, G., Mishra, S., Ray, B., Magee, L., Huynh, P., Canada, M., O’Donnell, D., & Flaxman, S. (2021). A modified two-process Knox test for investigating the relationship between law enforcement opioid seizures and overdoses. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 477(2250), 20210195. https://doi.org/10.1098/rspa.2021.01951364-5021, 1471-2946https://hdl.handle.net/1805/29573Recent research has shown an association between monthly law enforcement drug seizure events and accidental drug overdose deaths using cross-sectional data in a single state, whereby increased seizures correlated with more deaths. In this study, we conduct statistical analysis of street-level data on law enforcement drug seizures, along with street-level data on fatal and non-fatal overdose events, to determine possible micro-level causal associations between opioid-related drug seizures and overdoses. For this purpose, we introduce a novel, modified two-process Knox test that controls for self-excitation to measure clustering of overdoses nearby in space and time following law enforcement seizures. We observe a small, but statistically significant (p < 0.001), effect of 17.7 excess non-fatal overdoses per 1000 law enforcement seizures within three weeks and 250 m of a seizure. We discuss the potential causal mechanism for this association along with policy implications.en-USPublisher PolicyKnox testopioid seizuresoverdosesArticle