The relationship between gun ownership rate and the homicide rate is clear. They’re closely connected.

So just how closely correlated are they?

Well, in fact, the rate of gun ownership explains 76% of the variation in the rate of homicides over 41 years (76%=r-squared value).

No, that’s not all of the variation, I can already hear the gun crowd knee-jerk reacting now. (For the record, nothing will ever please them, let’s be honest. This post isn’t even trying to make the pro-gun-at-any-cost crowd happy. Nothing will. They’ll find any excuse under the sun to dismiss anything in anyway remotely negative about guns.)

But for the record, when one independent variable explains 76% of the change in a dependent variable, that’s a lot. It’s the overwhelming majority, in fact.

Now, what exactly is happening in this chart above, which uses General Social Survey, or GSS, and FBI data?

Between 1973 and 2014, as the rate of gun owners fell, so did the rate of homicides.

In 1973, 47% of American households had at least one gun, according to GSS data. By 2014, only 31% of American households had at least one gun, according to the same data source–the only source of data allowing more than 4 decades of analysis in gun ownership rates.

And in 1973, 9.4 out of 100,000 Americans were murdered every year. By 2014, 4.5 out of 100,000 Americans got murdered every year.

In other words, as the gun ownership rate fell by 34%, the chances of getting murdered fell by 52%. That is, as fewer Americans per capita were gun owners, the chances of getting killed fell.

Of course, it’s not a perfect one-to-one relationship. (You know what is nearly an exact one-to-one relationship? Firearm rate and the firearm death rate, see this link here.) It’s pretty hard, if not impossible, to find a perfect one-to-one relationship between two variables outside of physics and chemistry, ok? That doesn’t mean one thing doesn’t cause another. At all.

So let’s explore this a little further:

Why isn’t the gun ownership rate a complete one-to-one relationship?

Well, because not all murderers use guns, obviously.

No one ever suggested all homicides are committed with firearms. No one ever said a society without guns would have zero murders. No one.

As police well know, murders are a function of motive, method and opportunity. Aka Murder=f(motive + method + opportunity).

All three ingredients must be present for a murder, or any other crime.

The gun ownership rate has nothing to do with motive, but it has a lot to do with method and opportunity.

Guns are the preferred method. They’re the overwhelming method of choice for murder.

Why?

Well, because they expand the range of opportunity.

Firearms do three things that no other weapons (besides missiles and bombs) allow.

Guns project force farther than any other weapon. How many drive-by murders are committed using knives, bows and arrows or spears? Lee Harvey Oswald didn’t need to be next to JFK. He assassinated the President from 80 yards away. They’re more lethal than any other weapon. Bullets can do more damage than a punch to the face or a stabbing. If this weren’t the case, why in hell would every army in the world give soldiers firearms instead of nunchucks or longbows? By projecting force farther than any other weapon, guns provide murderers distance from their victims. And why is distance important? Because most murderers don’t want to get caught or hurt in the act of killing. No other weapon (save missiles and bombs) expands the distance between murderer and murdered as far as firearms. Being close means increased risk of getting hurt, killed or caught in the act.

So to pull it all together here, other weapons are not perfect substitutes for firearms because no other weapon projects force farther and more lethally, increasing the chances of successfully killing a victim and decreasing the chances of getting caught.

And because other weapons aren’t perfect substitutes even if motives to murder don’t chance in a society, the decreased availability of the most lethal method decreases the opportunity of murdering.

The evidence shows it.

When America had more gun owners per capita, the chances of getting murdered were higher.

As the rate of gun ownership has fallen over the last 4 decades, the odds of getting murdered in America have fallen substantially.

Remember: this is about gun ownership, not the number of guns owned. Those are two very different concepts.

Even though the number of guns owned in this country has skyrocketed, there are fewer gun owners. In other words, gun owners these days have a lot of guns, but guns don’t kill people–people with guns kill people. If a gun owner who already has 15 guns buys 100 more guns, the marginal lethality of each new gun is minimal to nonexistent because one gun owner can only use two guns at a time. But if 100 new gun owners are created, then we should expect to see more murders.

So society, the data tell us, is safer when a few people have tons of guns than it is when a ton of people have a few guns each.

Get the difference?

How do these data showing the murder rate has fallen along with a decline in gun ownership comport with the TV coverage showing a lot of mass murders?

This is how:

Although the odds of getting murdered in this country have fallen by 52% between 1973 and 2014, the odds of getting murdered in a mass shooting have increased.

And why is that?

Well, clip size of guns has increased. Relevance? A larger clip or magazine allows a murderer to shoot more bullets in less time.

So while the murder rate has gone down with the gun ownership rate, the mass murder rate has gone up with the increase in clip size.

OK, that’s it for now.

Just remember:

As the data clearly clearly show the murder rate is a function of the gun ownership rate.

To summarize, lower gun ownership rate decreases the availability of firearms, which decreases the opportunities of successfully killing someone. And when opportunities for murder decrease, then one of the 3 necessary ingredients for murder decreases.

Fortunately, the 18% point discrepancy between the murder rate and gun ownership rate likely reflects a decrease in motive over the past 4 decades. But government policy can’t change people’s motives to murder. But increased background checks can reduce (never completely) gun ownership rates.

For an expanded discussion of why regulating gun ownership makes more sense than regulating anything else, click here.