Tens of thousands of us must have told incredulous Americans when we travel over there or they travel here about what happened after John Howard changed our gun laws in 1996. Just 12 days after the Port Arthur massacre where 35 died and another 23 were seriously injured, the Australasian Police Ministers' Council adopted the National Firearms Agreement.

The centrepiece of the law reforms was the outlawing from civilian ownership the rapid-firing, mass-killing machines that armed forces carry.

Carolyn Loughton at the funeral of her daughter, Sarah, a victim of the Port Arthur massacre, in 1996. Credit:Angela Wylie

In 2016 with two colleagues, I published a report in the Journal of the American Medical Association where we told the world that 20 years on, Australia had not had a single mass shooting. In the 18 years up to and including the Port Arthur massacre, we’d had 13 where five or more (not including the perpetrator) were killed.

The New Yorker named our evaluation of the impact of the new laws as one of five most notable medical research reports of 2016.