Incidence of assault in Sydney, Australia, throughout 5 years of alcohol trading hour restrictions: controlled before‐and‐after study

Background and aims In February 2014, pubs and bars in Kings Cross (KX) and the central business district (CBD) of Sydney, Australia were required to stop serving alcohol by 3 a.m. and operate a ‘lockout’ from 1.30 a.m. We studied changes in the incidence of assault during the following 5 years, including possible displacement. Design Controlled before‐and‐after ecological study. Setting Sydney, Australia. Participants/Cases Assaults in specified areas in which police apprehended at least one person. Measurements We compared change in non‐domestic assault in KX and the CBD with adjacent areas, other city areas, and outer suburbs, adjusting for the trend in the rest of the state during three periods: 6 p.m.–1.29 a.m. (‘pre‐lockout’), 1.30 a.m.–2.59 a.m. (‘lockout’) and 3 a.m.–6 a.m. (‘after last‐drinks’). We constructed interrupted time‐series models with terms for secular trend and season, producing incidence rate ratios (IRR) for step and slope parameters. We performed sensitivity analyses on impacts of missing location data. Findings After the intervention, assaults fell 38% in KX (IRR for step change = 0.62, 95% CI = 0.49, 0.79) and 10% in the CBD (IRR = 0.90, 95% CI = 0.80, 0.99). Assaults continued declining in KX (IRR for slope = 0.990, 95% CI = 0.982, 0.998) and later increased in adjacent areas (IRR for slope = 1.006, 95% CI = 1.001, 1.011) and earlier in the evenings in both KX and the adjacent areas. The net reduction was 627 assaults over 60 months post‐intervention, i.e. 10 fewer per month. Estimates were robust to extreme assumptions about missing data. Conclusions The 2014 alcohol supply restrictions for pubs and bars in Kings Cross (KX) and the central business district (CBD) of Sydney, Australia were followed by a substantial reduction in the incidence of assault in KX and to a lesser extent in the CBD, possibly displacing some cases to adjacent areas and earlier in the evening.