Data and the Issue of Gun Control

Professor of Physics

I am continually surprised by the minimal role data plays in our discussions of guns, gun rights, and gun control. I see another example of this in the recent opinion piece in the Bates Student entitled “Gun Control is Essential.”

I think most of us believe that American society is becoming more violent, that the number of crimes committed each year with firearms is increasing and that we need to do something about it. However the crime reports published by the FBI show this perception is incorrect. The FBI’s webpage “Crime in the United States 2012,” shows, in Tables I and IA, that the number of violent crimes per 100,000 people has dropped every year from 747.1 in 1993 to 386.9 in 2012, or by 18.7% in the twenty year period. The “Expanded Homicide Data” in Table 8 shows that the total number of murders per hundred thousand people committed with a firearm (rifle, shotgun, handgun, and unspecified) has gone from 3.70 in 2008 to 2.82 in 2012.

One surprising piece of information in Table 8 is that the number of murders committed with “Personal Weapons” – examples of which are hands and feet – exceeded the number of murders committed with rifles and shotguns combined every year from 2008 to 2012

Lest I be accused of “cherry-picking” the data by choosing the years over which it is quoted, let me say that as far as I can tell, “Expanded Homicide Data” is only reported in five year intervals whereas violent crime is reported in twenty year intervals. In each case I’m looking at data from the last time-interval reported.

I was surprised by this data and my guess is that others will also find it surprising. After studying the FBI tables my first question was is the data accurate? FBI crime statistics are compiled from yearly reports submitted by essentially every law enforcement agency in the country, so the data should be accurate. My second question was why does the data surprise me? In other words, why did I think the number of violent crimes, and in particular, the number of murders committed with a firearm, was increasing? My guess is that the reporting of the news media is biased, perhaps intentionally, or perhaps because it – like the opinion piece in last week’s Bates Student – over-emphasizes the dramatic “lone gunman” crimes without putting them into a larger context.

The opinion piece also discussed the recent successful recall of the two state legislators in Colorado who spearheaded the passage of “anti-gun” legislation earlier this year. The author of the opinion piece calls them “political martyrs” and wonders if they were voted out of office because “only the gun fanatics came out to the polls.” But an internet search on the CNN and Huffington Post websites finds that although the NRA contributed between $400,000 and $500,000 to support the recall, Mayor Bloomberg and “billionaire philanthropist” Elie Broad contributed $350,000 and $250,000 respectively to defeat it. More generally, even though opponents of the recall procured nearly 3 million dollars (compared to the $540,000 raised by its proponents), the recall was successful. So if only “gun fanatics came out to the polls” it wasn’t because opponents of the recall lacked the money to support their position.

Understanding the recall election and what it represents is complicated by questions of how much money was raised that didn’t have to be reported, how many of the votes were against the specific legislators rather than their position on gun laws, etc. Nonetheless, the articles on the CNN and the Huffington Post websites lead us to believe that even though the NRA and other supporters of the recall were outspent by a margin of almost six to one, the recall was successful. The opinion piece asks “So what happened?” and I think that is an excellent question.

The legislation passed in Colorado, which is still in effect, includes three parts: first, it bans ammunition magazines with more than 15 rounds, second, all dealers must perform a background check before selling any firearm, and third, private parties must perform the same background check as dealers on any firearm they sell (plugging the “gun show loophole”). Two parts of the Colorado legislation were put into law by the federal government in 1994, the Brady Handgun Prevention Act, better known as the Brady Bill, and the Federal Assault Weapons Ban. The former expired in 2004 and the latter in 2009. The Assault Weapons Ban outlawed certain specific firearms and made ammunition magazines with more than 10 rounds illegal. The Brady Bill required dealers to perform background checks using the National Instant Criminal Background Check System (NICS) on any person attempting to buy a firearm. Background checks were not required for sales between private citizens.

The data on the FBI website shows no noticeable change in the yearly decrease of violent crimes when the two laws went into effect and no noticeable change in the yearly decrease of violent crimes when they expired. This was one of the major reasons that neither law was renewed. Data on the effectiveness of requiring private parties to perform background checks is still not definitive. A study performed by the Bureau of Alcohol, Tobacco and Firearms (the BATF) in 2000 found that gun shows were a major source of illegal gun sales.

On the other hand, in 1997 the Bureau of Justice interviewed over 18,000 federal and state prisoners and found that only 0.8% said they had purchased a firearm at a gun show. More studies have been done, but each has been criticized and there are no clear conclusions.

Thus, of the three provisions in the Colorado legislation, two have been shown by the data on the FBI website to have no discernible effect on the number of violent crimes committed and the effectiveness of the third is still inconclusive. Consequently, contrary to what is stated in the opinion piece, there is no data to support the statement that the legislation passed in Colorado “will make our lives safer.”

Perhaps there is better data than what I’ve cited above, and indeed, finding and evaluating data that is reliable and unbiased can be difficult and time consuming. But I think, first, we need to search out all of the data we can find, even that which contradicts our beliefs, so our opinions (and opinion pieces) have a firm foundation, and second, we need to stay open to new data and allow our opinions to evolve accordingly.

6 Responses to "Data and the Issue of Gun Control"

  1. Cathie Whittenburg Posted on October 3, 2013 at 1:07 pm

    Professor Sermon,

    Thankfully, violent crime of all kinds has decreased in this country. But gun crime still remains a concern. Two-thirds of homicides involve a firearm. The U.S. still has the highest homicide rate of all developed countries.

    And while homicides have decreased in the past 10 years, gun shot injuries have increased. For every homicide victim who is shot and dies, seven people are shot and survive. Overall, more people are getting shot, but more people are surviving their injuries.

    As far as the Colorado recall election, the turnout rate was extremely low. In Senator Morse’s district only 21 percent of the registered voters voted.

    I am confused on a few of the points you make.

    Why compare murders committed with “personal weapons” to those committed with rifles and shotguns? Why not all guns? Also, note almost 20% of the firearms used in homicides are not even classified. We can’t know how many of those were rifles and shotguns.

    The Brady Act is still in effect. It did not expire in 2009.

    It should be noted that the gun show as we know it now – a large event with multiple licensed dealers that also allow private sellers to set up tables and sell guns with no background checks – did not appear in this country until the early 1990s. These events were not possible before the passage of the McClure-Volkmer bill. It is questionable if a 1997 survey can reflect the impact of this change in gun shows.

    Data does show that the assault weapons ban and the ban on high capacity magazines were effective. Following the implementation of the ban, ATF data shows the share of gun crimes involving assault weapons and large capacity magazines dropped. State data in Virginia showed a significant drop in the number of high capacity magazines seized by police during the ten years the ban was in effect.

    I agree, we need to search out all of the data we can find. Unfortunately, the gun lobby has worked hard to block gun data. In the 1990s, the NRA was able to push Congress to enact a ban on CDC funding for firearm violence research. President Obama has only recently worked to overturn this ban. New, robust research will do much to inform the gun control debate.

  2. Mark Semon Posted on October 14, 2013 at 7:18 am

    I would like to know where you are getting the data to back up your statements. For example, the last sentence of your first paragraph is something often stated but the data say otherwise. See, for example, this article in the Harvard Journal of Law and Public Policy: http://www.law.harvard.edu/students/orgs/jlpp/Vol30_No2_KatesMauseronline.pdf. and the raw data from the United Nations s given on http://www.nationmaster.com/index.php.

    The CDC as well as the Harvard School of Public Health are notoriously “anti-gun.”

    Can you give me links to the data you quote? I’ve given you two that disprove your statement that “the United States has the highest homicide rate of all developed countries.” If you look at Nationmasters, which is based on data from the UN, and compare crime in the US with crime in Australia, you’ll see that the raw data say that the US ranks 11th in the world, behind the UK and Australia, in the number of assault victims. The US ranks 7th in the world in the number of homicides with firearms and 14th in the overall number of homicides.

    The US ranks first in homicides with a firearm, but all firearms are illegal in Australia and the UK (for example) so, as the authors in the Harvard study above argue, it’s more realistic to look at homicide data than firearm data when comparing one country to another.

  3. Mark Semon Posted on October 14, 2013 at 7:22 am

    I’m also wondering, are you in the Bates community, an alumni, a parent, … ? Finally, you mis-spelled my name.

  4. Mark Semon Posted on October 14, 2013 at 7:36 am

    The history of the Brady Bill is more complicated. In 1997 the Supreme Court ruled that the provision of the Brady Bill which required states to perform background checks was unconstitutional. Most states agreed to continue the background checks anyway (see, for example, http://www.treasury.gov/press-center/press-releases/Pages/rr2157.aspx). You may be right about the other provisions of the Brady Bill, I haven’t reseached them and my original general statement could be wrong.

    Also, your points about high-capacity magazines are irrelevant because they were made illegal by the Brady Bill and whatever their numbers are has no correlation to crime rates.
    Thanks for you willingness to discuss these issues.

  5. Mark Semon Posted on October 14, 2013 at 7:41 am

    Oh, my purpose in comparing “personal weapons” to “murders committed with rifles and shotguns combined” was to show that more people are killed with hands, fists, feet, etc. than rifles and shotguns combined. Included under “rifles ” are “assault rifles,” so it would be more effective in reducing murders to ban hands and fists than to ban all rifles, much less “assault rifles.” To be honest, I”m not sure what an “assault rifle” is. I’m assuming it’s a rifle with an ammunition clip that holds more than … how many …. 10, 15 , ? rounds of ammunition.

    • Qianli Xiao Posted on October 31, 2013 at 3:38 pm

      Professor–Please don’t hesitate to use the “reply” buttons to the left of comments to keep the discussion rolling. An automated email notification will be sent to the user you are replying to. Otherwise, great article and great discussion.

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