Postulation is no substitute for evidence: a rejoinder to Shepherd & Page
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Our claims about the impact of liquor licensing reform in NSW would have been stronger if a suitable comparison site had showed no change in the level of assault post‐2008. We considered using Victoria as a comparison site until we discovered that the Victorian Police had begun targeting alcohol‐related violence at around the same time as NSW. It was the lack of a comparison site that prompted us to say our findings only ‘suggest’ that the legislative reforms to liquor licensing in NSW produced a substantial drop in assault. It was the same consideration that prompted us to acknowledge that we ‘cannot rule out the possibility that the decrease in assault is due to unmeasured factors’.
It is important to understand that what matters in science is not the result of any individual study, but the balance of evidence from multiple studies bearing on the same question. Had our findings contradicted those of many other studies addressing the same issue, it would have been premature to claim that the NSW liquor licence reforms appear to have reduced violence. However, as we pointed out in our paper 1, our findings are consistent with most studies that have examined the effect of changes to liquor trading hours on assault. We do not think we overstepped the mark on the totality of the available evidence.