Preventing suicide: a statistical analysis

PhD student Shanley Chong

For her PhD in statistics, Shanley Chong has been analysing how suicide patterns have changed over time, with marriage, unemployment rates, wars and economic Depression as possible risk factors.

"Suicide is a serious public health problem, and its causes are complex," she says. 

Using Australian Bureau of Statistics (ABS) data from 1865 to 1998 in New South Wales as the basis of her research, Chong has looked at age patterns and developed models describing how these have changed. She examined main suicide age trends, asked whether suicide increased with age, and contrasted younger and older age groups.  

During the last century, these patterns changed considerably, especially for males over the last 30 years. Younger men have increasingly tried to kill themselves, using such methods as guns, hanging and car exhausts.

“I wanted to find out what led to increased rates among younger males, as well as the differences between males and females," Chong says.

She found that rates remained constant among older males and women, with a decreasing ratio of female to male suicides among the young, and fairly constant in other age groups. Recently, the ratio for all age groups has converged to similar levels.  

During the World Wars, ironically, fewer young men killed themselves, since they were constrained by the discipline of the armed forces. Unemployment leads to fewer female suicides, except for younger women. There were fewer suicides among older women during the Depression of the 1930s, and Chong says that the role of women aged 40-plus as mothers may protect them from suicide. Women also use different methods to attempt to kill themselves, such as drugs. These may prove to be less lethal. 

"Knowledge of factors causing suicide in the past can provide important information for preventing it in future," she says.

She would like to find further historical data to add to the ABS figures, to provide an even more detailed picture. 

"I think my research can draw attention to risks for, and methods used by young male suicides, so those in danger can be monitored," she continues. "Social and economic factors should also be considered more fully."

She would like her work to be read by health and education policy-makers.  

Chong's next project deals with suicide among migrants to Australia. Patterns become more like local ones the longer people live here, she is finding. 

Chong has completed all her academic work - a Bachelor and Masters degree and her PhD - at Macquarie University. When she started university, she knew that she enjoyed maths, but was searching for a way of applying it to people and social problems. She changed her major to statistics, and has never looked back. In her post-doctoral work she would like to apply her skills to areas such as welfare and environmental policy.

"Numbers and models and theory can all be applied to health and other social policy issues," she says. 

For further information on Chong’s work, contact her at schong@efs.mq.edu.au  For information on other postgraduate research opportunities in statistics, contact Emeritus Professor Don McNeil at dmcneil@efs.mq.edu.au , or visit http://www.stat.mq.edu.au

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