"Why do we think it's okay for people to die by suicide when they are in our care?" Rafferty said. "If the number is not zero what's the right number?
"Suicide is not inevitable - it is a preventable illness."
Zero Suicide is a global movement committed to improving outcomes and closing cracks in suicide prevention. The Canterbury District Health Board has also adopted it.
Preventing suicide is about a lot of little things that add up, Rafferty explained. He compared it to staff trying to "stop the gaps" that open up when someone is in a vulnerable state.
One campaign, called "the big brew", which urges people to ask someone who seems distressed to have a cup of tea with them.
Instead of admitting people to sterile outpatient clinics, the trust thought "out of the box" and set up "life rooms" in libraries and shops around the city. These are places people can come for finance and employment support and for social connection. Rafferty said they ran knitting circles, stand-up comedy, cooking and anxiety and confidence courses. The difference is there's no "mental health" sign and the activities are called courses not treatments.
"People are keen to talk about mental well-being but not mental illness. All of us have mental wellness issues we occasionally need to address," Rafferty told the Herald.
"We're doing everything from very simple stuff like saying to people inside communities there's no harm to talk about suicide. It's the simplest, pain-free, cheapest intervention you can imagine.
"Life rooms, you'll not know who is a patient or who has come into use the computer. I think that's fantastic way to break down the stigma."
Another revelation was that restraining patients experiencing an aggressive episode actually retraumatised them. Over the past four years the trust has reduced using restraints by 40 per cent, and assaults on staff have halved.
In England the largest at-risk group for suicide is men in their 40s and 50s who live in areas of low employment or struggle with addiction. Managing triggers was key to survival, Rafferty said.
Military veterans are one group they work with who often have pos traumatic stress disorder. One of their triggers are loud, sudden noises. So every year on Guy Fawke's weekend the trust organises a fishing trip at a quiet countryside property.
For others a trigger could be the anniversary of a relative's death or relationship break-up. The trust would ensure they had extra support at this time.
Thorough safety plans for patients, involving friends and family and developing an artificial intelligence tool that detects crisis points are some of the other tools the trust had focused on.
A culture shift was also necessary to aim for zero suicides, Rafferty said. They valued a no blame culture where staff could be honest and learn from mistakes and also be transparent with patients' families if a suicide does occur.
Rafferty will speak at the Zero Suicide in Healthcare Practice Forum in Christchurch on Thursday.
Canterbury DHB psychiatrist and clinical director Steve Duffy, who will also speak at the forum, acknowledged it was difficult to target suicidal people if they hadn't engaged with mental health services. So instead they want to reduce factors which contribute to risk.
"Like farmers: we identify those under stress. It might be for financial reasons, droughts, farm management trouble and then provide practical support. Those people may or may not suicide but they are middle-aged men with access to firearms, who are quite isolated and under stress.
"It's not just about suicidal behavior itself but all the things that feed into that."
Duffy said suicide needed to become a national focus as well as a community focus. He wanted to see everyone educated to know how to talk to someone with suicide ideation and know what suicide services are available.
Close to 1 per cent of the population die by suicide; 8 per cent might make a serious suicide attempt and 40 per cent report having had serious suicidal ideation, Duffy said.
"I'd most like to see in a country of 4.5 million a clear national focus on suicide prevention and some central coordination and drive for the suicide prevention effort. Local initiatives are valuable of themselves, but they are not going to scale up and address the problem at a national level.
"It's a serious problem and it will take serious funding to shift it."
Labour leader Jacinda Ardern, at a suicident prevention rally in September, recommitted to reviewing mental health services and said she wanted mental health teams in every secondary school in the country.
She said she wanted to eventually bring the number of suicides in New Zealand down to zero.
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (Mon-Fri 1pm to 10pm. Sat-Sun 3pm-10pm)
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155
• Samaritans 0800 726 666
• If it is an emergency and you feel like you or someone else is at risk, call 111.
