One of the arguments put forward by gun proponents relates to the deterrent effect that they contend gun ownership has on reducing violent crime. The NRA’s suggestion of increasing armed guards in schools and colleges is based on the deterrent argument. There are those who argue that without the deterrent effect of pervasive gun ownership, violent assaults increase. This is an empirical statement, and therefore it requires empirical support to substantiate. This brings us to the area of statistics.

The National Crime Victimization Survey (1994) found that from 1987-92 about 83,000 crime victims per year (on average) used a firearm to defend themselves or their property, with three-quarters of these incidents involving a violent crime. Most of the victims were young black males, and only 35% of these cases involved defense against a gun-wielding assailant.

The National Self Defense Survey carried out by Gary Kleck and Marc Gertz (1995) surveyed 5000 households to determine the rate of self-defense usage of handguns. The survey found that 15.7% of gun defenders believed that someone “almost certainly” would have died had the gun not been used for protection, and “probably” would have died in another 14.2% cases. In 73.4% of these gun-defense incidents the attacker was a stranger. In 91.7% of these incidents the defensive use of a gun did not wound or kill the criminal attacker. In over half of these gun defense incidents, the defender was facing two or more attackers. In 79.7% of cases, the defender used a concealable handgun.

The main problem with these studies is that they only investigate perceptions – e.g., the perception of who is the attacker and who is the defender (most people would claim that they were the victim), and the perception of what might have happened otherwise if they didn’t have a gun (which is probably prone to exaggeration). Perception surveys like these do not constitute ‘hard’ data.

The only robust means to determine whether guns reduce violence is to examine examples where guns have either been banned or have been introduced and see if there has been an impact on the violent crime rate. Saying – as some do – that violent crimes have decreased in the United States, and therefore there is no need for gun control is a ludicrous argument.

First, such a decrease is unlikely to have any relevance to gun ownership due to the myriad of other explanations for the decline in violent crime rates. These factors include economic changes, law enforcement strategies and population changes, amongst others.

Second, the United States continues to lead the developed world in gun related homicides (which make up approximately two-thirds of all homicides according UNODC figures, with two-thirds of gun related homicides being suicides), and therefore still has a serious problem to contend with. The reduction of gun related homicides is one impact that we can say for certainty would result from a total gun ban, assuming of course that all guns are confiscated (which is not an easy task).

Unless it can be shown that gun related homicides would have occurred anyway (using other weapons instead), or argued that such deaths are justified if it reduces violence overall (i.e. the price that is paid for an increase in overall safety) – both assertions being extremely difficult to establish – then gun related homicides constitutes a problem irrespective of the issue of violent assault rates in general.

To determine the deterrent effect that gun control has on violence, it is necessary to look at places where gun control has been introduced or removed, and study the before and after trends. Limited measures (like bans on semi-automatic weapons) have been studied in the United States, notably during the Federal Assault Weapons Ban of 1994 that lasted 10 years. The ban on semi-automatic weapons was not implemented effectively, as it did not involve a buy-back scheme (meaning assault rifles previously purchased were kept by the owners), and manufacturers found ways to produce ‘post-ban’ assault rifles that accorded with the regulations but were virtually identical to those that were banned (Violence Policy Center, 2004).

The  Centers for Disease Control and Prevention (2003) studied the “assault weapon” ban and other gun control attempts, and found “insufficient evidence to determine the effectiveness of any of the firearms laws reviewed for preventing violence,” although pointed out “that insufficient evidence to determine effectiveness should not be interpreted as evidence of ineffectiveness.” A review of research on firearms by a National Research Council panel (2004) concluded that academic studies of the assault weapon ban “did not reveal any clear impacts on gun violence” and noted “due to the fact that the relative rarity with which the banned guns were used in crime before the ban … the maximum potential effect of the ban on gun violence outcomes would be very small….”

The question of whether guns reduce violence is best studied by looking at instances where total bans have been introduced. This has never occurred in the United States. The best we have is some States enforcing tighter restrictions than others. States like New York, Illinois, Columbia (Washington DC) and California have stricter gun controls than other States. There is no significant correlation between these states and crime rates. Washington DC has the highest rates for violent crime, murder and robbery in the nation, but the next three States with the highest murder rates – Louisiana, Missouri and Mississippi – have loose restrictions, as do the States with the next highest rates of violent assaults (Nevada and Alaska). Anyway, it would follow that a State with a high crime rate might consider introducing tighter restrictions on gun use. This does not mean there is a causal relationship between gun laws and crime – far from it.

This leads us to look overseas for relevant examples. The two best cases are Australia and the United Kingdom, each of which introduced widespread firearm bans in the wake of mass shootings that occurred in 1996 (the Port Arthur massacre in Australia and the Dunblane school shooting in the UK). Both these countries have cultures not all that dissimilar to the United States (that is, when compared to most other countries in the world).

As some gun proponents have pointed out, assaults have increased in Australia since the introduction of the gun ban in 1996, despite the gun related homicide rate falling approximately 50% (AIC, 2011). Australia’s violent crime rate of 766 per 100,000 (in 2010) (AIC, 2011) is comparable to the peak in rates of violent assaults recorded in the United States in 1991. In Australia this represents an increase of approximately 25% since 1996 when gun bans were introduced (623 per 100,000). Meanwhile, violent assaults in the United States have declined by a whopping 44% from the peak in 1991 when it was 758.2 assaults per 100,000 (FBI, 2010).  The decline in violent assaults in the United States seems unrelated to gun ownership (and is therefore not relevant to the debate), as there have been no sudden increases in gun ownership that correlate with the decline. But what of Australia?

Australia’s case is difficult to assess due to the potential effect of other factors that could explain the increase in the violent assault rate. One is the increased reporting of assaults against women and children as a result of government campaigns since the 1990s to draw attention to domestic violence and child abuse. This probably explains why the rate of violence reported against women and children has been greater than any other category (see this AIC discussion paper). The other change that occurred since the 1990s is the expansion of the drinking culture in Australia, with the emergence of widespread binge drinking practices among young people (Livingston, 2008). With alcohol implicated in anywhere from 23 to as much as 73 percent of all assaults (AIC discussion paper), its impact on the rise in the violent assault rate should not be underestimated.

When we look to the United Kingdom, which also introduced extensive gun bans after the Dunblane school massacre of 1996, we see a completely different picture, with violent crime decreasing by 50% since 1995 (Home Office Statistical Bulletin, No. 12/10). One interesting trend is that violence involving guns has actually doubled in the UK over approximately the same period. Having said this, gun related homicides in the UK are very low at 0.1 per 100,000, in contrast to the United States which has a rate of 3.2 (UNODC, 2011).

So what do the comparative statistics tell us? Probably not a great deal. First, the trends after the introduction of gun bans are mixed, and the trends cannot be confidently related to gun control anyway. Second, both Australia and the UK had low rates of gun related violence to begin with, which makes it difficult to measure impacts and, further, does compare all that well to the United States where gun related violence is much higher. Third, a sample of two countries is not sufficient to base any conclusions on, even if the trend data was more clear.

The only real means for determining whether gun control in the United States will have an impact on violent crime is to introduce gun control and see what happens. The ideal way would be to run an experiment that involves establishing an experimental group (a random selection of 25 states that implement gun control) and a control group (a random selection of 25 states that do not). In this way, the myriad of other factors that influence crime rates (including population changes, law enforcement reforms, and so on) can be ruled out.

Gaining broad support for such an exercise is unlikely. It would involve nullifying the 2nd Amendment (at least for the duration of the experiment).

We are therefore left to ponder total gun control in the United States as ‘what if’ without ever knowing ‘what is’. What we can say with some certainty, however, is that the notion of ‘more guns, less crime’ is not sufficiently supported in the available statistics. It also should be pointed out that the issue of violent assaults is not related to the issue of deaths by suicide, which accounts for approximately 60% of firearm related deaths in the United States (BJS, 2002), and also accidental injuries. Nor has the issue of non-fatal injury caused by assault with a firearm been considered. To really understand the impacts of firearms on crime and safety, it is necessary to look at the whole picture.

As President Obama announces his intention to overturn the 1996 ban on federally funded firearms research, we might dare to hope that some proper research is carried out. Perhaps then some rigour will be introduced into the gun debate that so far has been largely lacking. However, just like studies undertaken in the wake of  the Federal Assault Weapons Ban of 1994, it may be difficult to develop sufficient clarity on the impacts resulting from these limited reforms, assuming they pass through Congress (a big ‘if’).

Such experimentalism on such a serious issue might offend some people, but the intention is to gather ‘hard’ facts on an issue that might move us closer to a solution. The view from organisations like the National Rifle Association (NRA) that eliminating gun free zones (GFZs) in school areas by having armed teachers or guards is certainly one that could be tested by allowing a selection of schools to do this and then see what happens. Like any good program evaluation rationale, if it works, then you extend it.

It appears that only through a comprehensive ban on firearms in at least some States could the impacts on gun control and violence be properly studied. That would involve instituting bans in the absence of clear cut evidence to support it, but it will offer a clear-cut solution to the debate.

Just a final point to avoid some of the confusion that I have seen among those debating gun control. The issue of introducing bans on semi-automatic weapons is not so much about decreasing gun-related homicides but rather mass shootings where semi-automatic guns are the weapon of choice (see the website for a full list of mass shootings and type of weapons used). However, as discussed above, most regular shootings do not involve semi-automatic weapons, so banning these types of weapons will not have a significant impact on murders and suicide rates. I will have more to say about semi-automatic regulation and mass shootings in the next article.