Friday, April 17, 2015

In an article titled "Quentin Bryce urges focus on gender inequality to tackle domestic violence", published on April 6th, Guardian journalist Melissa Davey claimed that "Two women are killed through domestic violence in Australia every week, and it is also the leading preventable cause of injury and death in women under 45, according to VicHealth".

Men's Health Australia wrote to the Guardian explaining the following:

The latest data from the Australian Institute of Criminology found that, during the period 2010 to 2012, 121 females were killed by an offender with whom they shared a domestic relationship (1.2 per week). This rate would have to almost double to reach the two per week claim made by Davey.

The VicHealth data is also seriously misrepresented. They found that intimate partner violence is the biggest contributor to ill health and premature death in women aged 15–44. 82% of this burden of disease was from poor mental health (depression and anxiety) and substance abuse, while just 2.3% was from homicide and 0.7% from physical injury. The leading cause of death for Australian women 15-44 years is malignant neoplasms, and the leading cause of injury is "other unintentional injuries".

Congratulations are due to the Guardian, who have now corrected the article in question.

The article now reads as follows:

"On average at least one woman is killed as a result of domestic violence in Australia every week, and it is the biggest contributor to preventable ill-health and premature death in women under 45, according to VicHealth."

The Guardian also published a footnote reading:

"This article was amended on 16 April to correct the reported rate at which women are killed by intimate partners. Women die this way in Australia at the rate of slightly more than one a week, according to Australian Institute of Criminology statistics – 109 in 2010-11 and 2011-12 combined. Unofficial figures for the first few months of 2015 show a similar rate."

Unfortunately, Davey's article ignored the fact that the same Australian Institute of Criminology report found that one man dies as a result of domestic homicide on average every 10 days. It also ignored the many serious problems with the VicHealth factoid, including that:

The VicHealth Report was not subject to the peer-review process.

The researchers assumed that all violence experienced by women was intimate partner violence, hence considerably overestimating the magnitude of their burden of disease findings (we know that actually most violence against women is not domestic violence). The researchers assumed that anyone reporting 'ever having been in a violent relationship with a partner' was abused by their partner if also reporting current or past, physical and/or sexual violence.

Most lay people who hear this claim assume that it refers to causality, whereas it actually refers to risk factors. A risk factor is a variable associated with an increased risk of poor health. Risk factors are correlational and not necessarily causal, because correlation does not imply causation. For example, being young cannot be said to cause measles, but young people are more at risk as they are less likely to have developed immunity during a previous epidemic. When one looks at the top 5 actual causes of the burden of disease in young women, they are anxiety and depression, migraine, type 2 diabetes, asthma and schizophrenia. Violence, let alone the subset of domestic violence, doesn't make the list.

The researchers were at pains to point out that while there was a correlation between domestic violence and health impacts, their study design was unable to demonstrate causality (in other words, for example, women with mental health and substance abuse issues might become involved in more domestic violence, or women experiencing domestic violence might develop mental health and substance abuse issues, or most likely both - there's no way to tell).

The researchers were also at pains to point out that there remains considerable uncertainty around their estimates that can only be solved with better data sources.

The study found that 82 per cent of the burden of disease from intimate partner violence in young women was from poor mental health (depression, anxiety, eating disorders) and substance abuse (tobacco, alcohol, drug use).

The study found just 2.3 per cent of the burden of disease from intimate partner violence in young women came from homicide and 0.7 per cent from physical injury.

It may well be the case that violence is also the biggest contributor to preventable ill-health and premature death for men under the age of 45, but the study failed to study men because the only data available was for women.

Even if the VicHealth claim were true, it would not mean much. For example, if we could somehow prevent all death, illness and injury for women due to other risk factors, the burden of disease from violence would reach 100%. This would make it sound like things are getting worse when actually violence is staying the same while other factors are improving.

Unfortunately the above problems are glossed over whenever the media make this alarming claim which is regularly presented as a fact.

Domestic and family violence is a serious issue that affects the entire community - men, women and children. We need to get our facts right if we are to make inroads into reducing the levels of violence in Australia.