Gun-related violent crime in Virginia has dropped steadily over the past six years as the sale of firearms has soared to a new record, according to an analysis of state crime data with state records of gun sales.

The total number of firearms purchased in Virginia increased 73 percent from 2006 to 2011. When state population increases are factored in, gun purchases per 100,000 Virginians rose 63 percent.

But the total number of gun-related violent crimes fell 24 percent over that period, and when adjusted for population, gun-related offenses dropped more than 27 percent, from 79 crimes per 100,000 in 2006 to 57 crimes in 2011.

The numbers appear to contradict a long-running popular narrative that more guns cause more violent crime, said Virginia Commonwealth University professor Thomas R. Baker, who compared Virginia crime data for those years with gun-dealer sales estimates obtained by the Richmond Times-Dispatch.

"While there is a wealth of academic literature attempting to demonstrate the relationship between guns and crime, a very simple and intuitive demonstration of the numbers seems to point away from the premise that more guns leads to more crime, at least in Virginia," said Baker, who specializes in research methods and criminology theory and has an interest in gun issues.

The significance of Baker's analysis was questioned by one of the state's ardent gun-control advocates.

"I'm not surprised that it would appear that more guns is going along with less crime, because there's been a downward trend in violent crime anyway," said Andrew Goddard, president of the Virginia Center for Public Safety.

One of Virginia's most outspoken gun-rights supporters, Philip Van Cleave, president of the Virginia Citizens Defense League, was not surprised for a different reason.

"My opponents are constantly saying, 'If you got more guns on the street, there's going to be more crime.' It all depends on who has the handgun," Van Cleave said. "As long as it's going into the hands of people like you or me, there's not going to be a problem. Criminals are going to continue to get their guns no matter what."

At the request of The Times-Dispatch, Baker examined six years of data compiled by Virginia State Police through the Virginia Firearms Transaction Center that breaks down the number of gun transactions for every federally licensed firearm dealer in Virginia. It includes the number and types of guns they sought to sell based on requested state background checks of the purchasers.

Baker then compared the data with state crime figures for those years.

The data, Baker said, show a low probability that more guns in the hands of Virginians is causing more violent crime.

"So while it's difficult to make a direct causal link (that more guns are resulting in less crime), the numbers certainly present that that's a real possibility," Baker added.

The opposite - that more guns are causing more crime - cannot be derived from the numbers, he said.

"It's mathematically not possible, because the relationship is a negative relationship - they're moving in the opposite direction," Baker said. "So the only thing it could be is that more guns are causing less crime."

"From my personal point of view, I would say the data is pretty overwhelming," said Baker, who is new to VCU and studied under Florida State University professors Gary Kleck and Marc Gertz, whose nationally recognized research on guns and homicides in the District of Columbia was cited in a landmark U.S. Supreme Court decision in 2008 that overturned the district's handgun ban. "But we're pretty cautious in the social sciences in talking about causality. We only talk in probabilities."

The multiple years of data for gun purchases and gun-related crime help strengthen the premise that more gun sales are not leading to an increase in crime. Using what Baker calls the "lag model," the data show that an increase in gun purchases for one year usually is followed by a decrease in crime the next year.

Baker said a more detailed analysis may find pockets of the state where increased guns sales have been followed by an increase in gun-related violent crime.

"But I'm not interested in that small, nuanced component," he said. "As a scientist, you don't want to focus on individual instance. That's what gets people into making these overgeneralizations about things like some of the tragedies that have been gun-related in the United States."

The estimated number of gun purchases based on requested background checks rose from 243,251 in 2006 to a record-breaking 420,829 sales last year, according to gun-dealer transaction data compiled by state police through background checks. Over that same period, the total number of violent crimes in Virginia dropped from 23,431 offenses in 2006 to 18,196 in 2011.

The total gun purchases cover all types of firearms, including pistols, revolvers, shotguns and rifles. Similarly, total gun-related crime includes offenses committed with all types of guns, including firearms whose type was unknown.

Handgun-related offenses account for the majority of violent crimes committed in Virginia.

Because rifles and shotguns are used far less often to commit violent crimes, Baker said, one could argue that the purchase of those types of weapons is falsely inflating the total gun purchases in relation to total gun crime.

So Baker also examined the relationship between handgun purchases and handgun-related crime. He found a similar trend.

Handgun purchases in Virginia increased 112 percent from 2006 to 2011, but violent crimes committed with handguns fell by nearly 22 percent. When adjusted for population increases, handgun purchases rose a little more than 100 percent, but violent crimes committed with handguns dropped 26 percent, according to Baker's analysis.

Baker said this general pattern remains even if all crimes reported to police where the gun type was unknown are assumed to be handguns.

"In fact, if all unknown gun types used in violent gun crimes are assumed to have been handguns, then handgun-related violent crime decreased just over 24 percent from 2006 to 2011," he said.

However, Baker noted the pattern does not seem to hold in one crime category: aggravated assaults. Increases in gun purchases might increase the percentage of aggravated assaults involving a gun.

The data show that while the actual number of aggravated assaults decreased from 2006 to 2011, those committed with a gun increased nearly 2 percent. Baker said that's not surprising. Studies have shown similar results for an increase in the number of guns and an increase in the percentage of suicides by a gun.

The percentage of aggravated assaults in which guns are involved may increase, but it has little effect on the actual rate or number of those offenses, Baker said.

"This is why we do not see an increase in aggravated assaults associated with an increase in gun sales, but rather an increase in the percent of aggravated assaults which used a gun," he said.

Baker said some researchers suggest that the use of a gun in an assault increases the lethality of such encounters, and that a similar assault without a gun reduces the probability of a homicide occurring.

But Baker said it bears noting that Virginia's homicide rate, like violent crime generally, has dropped from 5.21 killings per 100,000 Virginians in 2006 to 3.77 per 100,000 in 2011.

Baker, who owns a handgun and had a concealed-carry permit when he lived and worked in Florida, described himself politically as "moderate to conservative." But he says his research is nonpolitical. "I try to think of myself as a scientist," he said.

Van Cleave, the gun-rights advocate, said Baker's analysis confirms what he already suspected.

"Doing what I do, I have my finger on the pulse of gun sales, and I know they've been soaring because I'm at gun shows and I've talked to dealers and all I hear is the stories about how guns are selling at a higher rate now than ever," Van Cleave said. Simultaneously, "we've been hearing in the news about how violent crime has been dropping in the United States for over a decade."

"Never before have you had so many new guns come into the market," Van Cleave said. "That probably helped (Baker's) analysis and dramatized more than anything that all those guns - for whatever reason - didn't make crime go up."

Gun-control lobbyist Goddard, whose son was wounded during the Virginia Tech massacre five years ago, doesn't dispute the numbers but questioned their significance.

"It's quite possible that you can sell a whole lot more guns and crime is still going down," Goddard said. "But is the crime going down because more people are buying guns, or is the crime going down because the crime is going down?"

Goddard said he would not have expected a rise in crime from a rise in legal gun sales, because legal gun buyers are not usually criminals - otherwise they would not pass a background check to get them. "Predicting the actions of criminals by analyzing the behavior of legal gun buyers is not likely to be productive," he said.

What is more significant, Goddard said, is that the large reduction in violent crime has not produced an equivalent reduction in total gun deaths and injuries.

"If you look at the numbers of people who are dying from guns every year, including suicides and accidents, then you're not going to see a difference," he said. "Gun sales are going up, and the annual death rate in Virginia is staying pretty much constant."

Baker said the perception that guns cause crime is pervasive because criminals use an effective tool to carry out their misdeeds.

"It does an effective job for what it's supposed to do," he said. "And because criminals use them, I think it becomes a hot-button issue, it becomes a political issue. And people focus on the wrong component of what the problem is."

"Instead of trying to figure out why are these people committing crimes - and using the most effective tool to commit those crimes - they focus on the tool," he continued. "So the gun is causing the crime."

mbowes@timesdispatch.com (804) 649-6450