Link Between State Gun Laws and Fatal Shootings Not as Simple as It Seems 各州枪支法与致命枪击案的关系并不像看起来那样简单 作者：Thomas A. Firey @ 2015-10-11

译者：尼克基得慢（@尼克基得慢）

校对：小册子（@昵称被抢的小册子）

来源：Reason， https://reason.com/archives/2015/10/11/about-that-national-journal-gun-chart America has resumed its long-running debate on gun control, following the terrible attack at Umpqua Community College in Roseburg, Oregon, last week and two more shootings Friday, at Northern Arizona University and Texas Southern University. This time around, perhaps nothing has gotten more play than this table from a short column by National Journal graphic artist Libby Isenstein.

在上周俄勒冈州罗斯堡乌姆普夸社区大学的可怕袭击和本周五北亚利桑那大学及德克萨斯南方大学的两起枪击案之后，美国有关枪支管制的长期争论再次开启。这一次，可能没什么比《国家杂志》平面艺术家Libby Isenstein在一篇简短专栏文章里的这张表格更出风头的了。

The chart ranks the states by their rate of "gun-related deaths" and notes whether each state has gun-restricting laws like background checks and waiting periods, or laws that expand gun accessibility and use, like concealed-carry and stand-your-ground rights. The chart’s implication is clear: the more gun restrictions, the fewer horrible crimes.

这张表格将各州按“涉枪死亡”率排名，并且标注了每个州是否有诸如背景审查和等待期这样的枪支管制法律，或者像隐蔽携带和无须退让权【 译注："stand-your-ground" law是一种支持强自卫权的法律，允许个人在合理的认为自己身体或生命面临威胁时，不经退让躲避即可使用致命武力实施自卫。 】这种扩大枪支获取和使用的法律。这表格的含义很明显：枪支管制越严，恶性犯罪越少。

Isenstein’s chart has since been posted on countless blogs, Twitter feeds, and Facebook pages, with the subtext (and often the explicit text) that if troglodyte gun-rights supporters could appreciate simple statistics, they’d stop impeding common-sense gun controls that would deter terrible crimes like the one in Roseburg. President Obama also made this point explicit last week in a statement about the Roseburg shooting:

Isenstein的表格至今已经被无数的博客、推特和Facebook页面转载，潜台词（而且经常是明说）就是，如果赞成持枪权的老顽固们能够领会这简单的数据统计，他们就不会再阻止常识性的枪支管制，像罗斯堡那样的恶性犯罪就不会发生。奥巴马总统上周在关于罗斯堡枪击案的一份声明中也明确表达了这一观点。

States with the most gun laws tend to have the fewest gun deaths. So the notion that gun laws don’t work, or just will make it harder for law-abiding citizens [to obtain guns] and criminals will still get their guns, is not borne out by the evidence.

枪支管控法最多的州往往枪击致死的人数最少。所以认为枪支法不起作用，或者认为它们仅仅使守法公民[获得枪支]更加困难而犯罪分子将仍然得到枪支的看法，是没有证据支持的。

The president’s comment has since received some critical scrutiny from The Washington Post's "Fact-Checker" Glenn Kessler. And UCLA law professor and Post contributor Eugene Volokh criticized the National Journal table in a recent post on the lack of a statistical link between gun control and overall homicide rates.

总统的观点已经被《华盛顿邮报》“真相检查者”Glenn Kessler仔细推敲过了。加州大学洛杉矶分校法学教授、《华盛顿邮报》投稿人Eugene Volokh在最近一篇文章中批评《国家杂志》的上述表格缺乏枪支管制和整体谋杀率之间的统计学关联。

Yet the chart continues to bounce around the Internet and the media. Its currency reveals how readily people seize on statistics they don’t really understand but think—in this case, wrongly—support their opinions, claiming the intellectual high ground while dismissing opposing viewpoints as hopelessly ignorant, biased, and dishonest .

然而这个表格在互联网和媒体上持续发酵。这一趋势反映了人们多么倾向于利用他们并不真正理解但（错误地）认为支持其观点的统计数据，来占领智识高地并将相反观点斥为无可救药的无知、偏颇和不诚实。

First, let’s be clear about what Isenstein’s chart does show: a connection between "gun-related deaths" and certain gun laws. A simple statistical test offers decent evidence of such a relationship. But there’s a problem with using that evidence to conclude that more gun restrictions will reduce the number of fatal shootings. To understand why, consider the following story.

首先，让我们来搞清Isenstein的表格真正表达的是什么：涉枪死亡人数和某些枪支管控法之间的关联。一个简单的统计测试就能提供这种关系的有力证明。但是用这种证据得出加强枪支管制就会减少致命枪击案的结论是有问题的。为了理解当中的原因，请思考下面这个故事。

Suppose there are two towns, Chevyville and Fordburg. Many years ago, General Motors (GM) built a factory in Chevyville and its residents, in loyalty to their town’s largest employer, now all drive Chevrolets. In Fordburg, however, local leaders were so angry with GM for not building the plant there that they passed an ordinance banning Chevrolets.

假设有两个名为Chevyville 和 Fordburg的小镇。很多年前，通用汽车在Chevyville建了一个工厂，该镇的居民都忠于镇上最大的雇主，全都开雪佛兰汽车。然而在Fordburg，当地的领导人因通用不在该镇建厂而愤怒地通过了一条禁止雪佛兰汽车的法令。

Recently, some Chevyvillians noticed that every fatal car crash in town involved a Chevrolet, whereas Fordburg hasn’t had a fatal Chevy crash in years. Those folks assembled a damning chart comparing Chevyville and Fordburg’s Chevrolet-related fatal crashes and began demanding that Chevyville adopt Fordburg’s Chevrolet controls.

最近，一些Chevyville居民注意到镇上每起致命的车祸都与雪佛兰相关，然而Fordburg很多年都没有致命的雪佛兰车祸。于是这些人制作了一份表格，证据确凿地比较Chevyville和Fordburg两镇与雪佛兰相关的致命车祸数，并开始要求Chevyville实行同Fordburg一样的雪佛兰汽车管制。

The Chevyvillians aren’t really upset about Chevrolet-related fatal crashes, but about fatal crashes in general. It’s quite possible that Chevy-free Fordburg has the same rate of fatal crashes as Chevyville, but Fordburg’s crashes involve Fords, Dodges, and Toyotas. That becomes obscured by Chevyvillians’ focus on Chevrolets. If Chevyville’s leaders, persuaded by the chart, were to ban Chevrolets, residents would likely continue suffering the same fatal crashes they do now, just with other car brands.

Chevyville居民并不是为与雪佛兰相关的致命车祸感到难过，而是为所有致命车祸感到难过。没有雪佛兰的Fordburg很可能与Chevyville有相同的致命车祸率，只不过Fordburg的车祸涉及福特、道奇和丰田的车子。但这些事实都被Chevyville居民对雪佛兰的关注所掩盖了。如果Chevyville的领导听信表格而禁用雪佛兰汽车，居民们很可能仍然会面对跟现在同样的致命车祸，只不过换了别的汽车品牌而已。

Isenstein (and many others )) makes a similar analytical move as the Chevyvillians: she focuses on gun-related deaths rather than all violent deaths. Her table shows that, in states where it’s easier to buy and carry a gun, violent deaths are more likely to occur from guns—but that doesn’t mean the violent death rate is higher in those states.

Isenstein（还有很多其他人）的分析跟Chevyville居民类似：她关注涉枪死亡人数而不是所有的暴力死亡人数。她的表格显示，更容易买到和携带枪支的州更可能发生枪支导致的暴力死亡——但是这并不意味着这些州的暴力死亡比例更高。 Statistical testing 统计检验 The question that lies at the heart of the gun control debate is whether gun restrictions reduce the incidence of murder and other violent crime. To help answer that, we can compare Isenstein’s state law data to murder and violent crime rates from the Bureau of Justice Statistics’ Uniform Crime Reports (UCR).

枪支管制辩论的核心问题，在于限制枪支是否能减少谋杀和其他暴力犯罪的发生率。为了回答这一问题，我们可将Isenstein的各州法律统计数据与司法统计局统一犯罪报告（UCR）的谋杀和暴力犯罪率相比较。

I did this with UCR data from 2012 (newer data aren’t yet available), resulting in 14 total test results (Isenstein’s seven laws multiplied by the two types of crime). The statistical test, known as a Pearson’s r, returns a value between 1 (indicating perfect positive correlation ), 0 (no correlation), and –1 (perfect negative correlation). I arranged the tests so that negative numbers would indicate a relationship between more gun control and less violent crime.

我比较了2012年的统一犯罪报告，得出了总共14项检验结果（Isenstein七个方面的法规状况乘以两种犯罪类型）。这种称为Pearson积矩相关系数的统计检验会得出一个在1（表示完全正相关）、0（没有关联）、和-1（完全负相关）之间的值。在我组织的这个测试里，负数表示更多枪支管控法和较少暴力犯罪之间存在联系。

The results: In half of the 14 tests, the resulting coefficients were positive numbers, meaning that Isenstein’s gun restrictions had no more than a coin-flip chance of yielding the results that gun control supporters expect. Moreover, in all 14 cases, the coefficients were tiny, with nine smaller than +/– 0.1. Those results should make us highly skeptical that the gun laws have any effect—positive or negative—on murder and violent crime.

结果：在14项检验中，有7项得到的系数是正值，说明Isenstein的枪支限制得到枪支管制支持者预期结果的几率不会比抛硬币更高。而且，在全部14项检验中，相关系数都很小，有9项小于+/-0.1。这些结果应让我们高度怀疑，枪支法规是否对谋杀和暴力犯罪有任何影响——无论是正面的还是负面的。

I then slightly altered her law data in light of some peculiar data choices she made. For instance, Isenstein assumed that gun control changes implemented in 2015 affected gun-related deaths in 2013. She also treated states with court-established stand-your-ground (SYG) rights the same as states with no SYG, and different from states with legislatively enacted SYG rights. I used gun law data for 2012 (to match the crime data) and coded legislature-enacted SYG and court-imposed SYG the same.

然后我针对她对数据的一些特殊选择，稍微调整了她的法律统计数据。例如，Isenstein假定枪支管制法规在2015年发生的变更影响了2013年的涉枪死亡人数。她还将法院支持不退让权的州等同于没有不退让权的州，并且与立法确立不退让权的州区别开来。我用了2012年的枪支法规统计（为了匹配犯罪数据），并且将立法实行不退让权和法院承认不退让权等同视之。

I then repeated the statistical tests and the results were much the same as before. This time, nine of the 14 tests yielded positive numbers, indicating a correlation opposite of what gun control advocates expect. (In case you’re wondering about universal background checks, which President Obama is now considering expanding through executive order, both the murder and violent crime coefficients were positive numbers.) And again, all of the coefficients were tiny, with nine smaller than +/-0.1.

然后我再次进行了该统计检验，而结果跟之前相差无几。这一次，14项检验中有9项得到正值，显示与枪支管制支持者所预期的相关性相反。（若你想了解奥巴马总统正考虑通过行政命令来扩大的普遍背景调查的检验结果，我可以告诉你，它与谋杀和暴力犯罪的相关系数都是正值。）所有的系数都还是很小，有9个小于+/-0.1。

Finally, mindful of the possibility that a combination of gun laws could produce a "compounding" effect that alters crime rates but is undetectable when the laws are considered separately, I created an overarching variable intended to distill all of Isenstein’s law data into a single "gun restrictive" measure for each state. For violent crime, the resulting coefficient was 0.093 (again, a positive number, contrary to gun control advocates’ expectation), while murder was –0.012 (a negative number, but extremely tiny even when compared to the other tiny coefficients).

最后，枪支法规组合在一起时可能会产生影响犯罪率的“复合”效应，但在个别考察枪支法规时该效应未必能够被发现。考虑到这种可能性，我创造了一个全局变量，旨在将Isenstein的所有法规统计数据浓缩成每州一个的枪支限制程度值。对于暴力犯罪，得到的系数是0.093（又是正值，与枪支管制支持者预期相反），而谋杀的系数是-0.012（负值，但即使与其他很小的系数相比都极小）。

The results weren’t all bad for gun control. I performed the same statistical tests on 2012 state suicide rates and found that five of the seven coefficients yielded negative numbers, which is what gun control supporters would expect. Two of the cases (handgun registry and open-carry) yielded coefficients as large as –0.267 and –0.254—still pretty small, but much bigger than the crime coefficients.

结果并不是都不利于枪支管制。我对2012年各州自杀率做了同样的统计检验，发现得到的七个系数中有五个都是枪支管制支持者所期望的负值。有两项检验（手枪登记和公开携带）得到的系数较大，分别是-0.267和-0.254——仍然非常小，但比犯罪的系数要大得多。

So maybe gun control does have a small, beneficial effect on suicide. And it’s worth noting that nearly two-thirds of gun deaths are suicides . But currently the argument over gun control isn’t driven by concerns about suicide, but about violent crime.

所以或许枪支管制对减少自杀有微弱的有利影响。值得一提的是，近三分之二的涉枪死亡是自杀。但是如今有关枪支管制的争论并不是因为担心自杀，而是暴力犯罪。 Correlation, causation, and complexity 相关性，因果关系和复杂性 As damning as all this might appear, it shouldn’t be interpreted as proof that gun control (or gun access for that matter) has no effect on violent crime. My analysis suffers two serious shortcomings, which also plague Isenstein and her re-posters.

虽然看起来证据确凿，但上述分析并不应该被视为枪支管制（或者说枪支获取）对暴力犯罪没有影响的证明。我的分析有两个严重的漏洞，Isenstein和她的转发者们也面对同样的问题。

The first is the old dictum that correlation does not prove causation. Assume for a moment that our tests yielded stronger correlation coefficients; we still wouldn’t know whether they indicate that laxer (or tighter) gun controls led to higher murder and violent crime rates, or if the higher crime rates led to laxer (or tighter) gun controls as a result of public demand for different gun laws. Or some other cause could produce both higher murder rates and changes in gun laws.

第一个问题正如那句古老格言所说，相关性并不能证明因果关系。暂时假设我们的检验得出了强相关性，我们仍旧不能确定它们是否就表明更宽松的（或更严格的）枪支管制导致了更高的谋杀和暴力犯罪率，抑或是更高的犯罪率改变了公众对各类枪支管制法规的需求，从而导致了更宽松的（或更严格的）枪支管制。又或者，有一些其他原因能够同时导致更高的犯罪率和枪支法规的改变。

Another problem is that many factors besides gun laws likely affect murder and violent crime rates (and suicides, for that matter—see Kessler's and Volokh's columns for more on this). Controlling for those factors could reveal different relationships (or non-relationships) than what Isenstein's table and my analysis suggest.

另一个问题是，除了枪支法规外还有很多因素也可能影响谋杀和暴力犯罪率（自杀也同样适用——更多信息请查阅Kessler和 Volokh的专栏）。调控了这些因素后所揭示出的关联性（或者非关联性），也许与Isenstein的表格和我的分析所显示的关联性并不一样。

Advanced statistical methods may be able to overcome those problems, and plenty of trees have been felled to provide paper for such academic analysis of American gun laws. Problem is, there's hardly a consensus among researchers as to whether any causal relationship has been found. (For a sense of the literature, see this .) The United States is hardly alone in this.

高级统计方法或许能克服这些问题，而有关美国枪支法规的这类学术分析已经汗牛充栋了。问题在于研究者对于是否发现了因果关系很难达成一致。（想感受一下相关文献，请看这里。）并不是只有美国面对这一问题。

For instance, though gun control advocates are now lionizing Australia's 1996 National Firearms Agreement restricting the licensing and ownership of different weapons, there appears to be no consensus among researchers as to whether the policy has reduced Australian homicide rates. (There does appear to be consensus that it has reduced suicide rates, though some researchers reach different conclusions.)

例如，虽然枪支管制的倡导者如今将澳大利亚的1996年国家枪支协定奉为杰作，该协定限制各种武器的许可和持有，但是研究者对于该政策是否降低了澳大利亚的谋杀率似乎并未达成共识。（人们在该政策能降低自杀率这点上倒似乎达成了一致，尽管有些研究者得出了不同结论。）

The difficulty with this research is that it's hard to compare outcomes in the real world to outcomes in a hypothetical world where different gun laws exist but everything else is the same. Hence researchers' use of advanced mathematics and statistics. The problem is, unless you have a Ph.D. in some statistical science and a good appreciation of the specific issues involved in gun research, you'll be hard pressed to understand the critical points of that research, let alone form a knowledgeable opinion about which analyses are most likely correct.

这项研究的难度在于很难将现实世界的结果与假想世界的结果相比较，在假想世界中除了枪支法规不同外，其他所有条件都一样。然后研究者使用高等数学和统计学进行分析。可问题是，除非你有统计学的博士学位，而且对于涉枪研究的具体问题有深入的认识，否则你很难理解这一研究的关键点，更不用说对哪个分析更可能正确发表真知灼见了。

That brings us to the derisive comments accompanying all those posts of Isenstein's table. We now know the snark is misplaced. So why is the gun control debate, and American politics in general, so rife with such nastiness?

现在我们再来看那些针对转发Isenstein表格的嘲讽评论帖子。我们现在知道这些尖刻评论是不对的。那为什么枪支管制的辩论，以至普遍的美国政治，都有如此之多的龌龊事？

Part of the reason, understandably, is the stakes: gun control and gun rights involve some of the most cherished human values, including public safety, self-preservation, defense of innocents, privacy, and property rights. Part of the reason is simple fear: many people believe their risk of being victimized by violence is increasing (though the data show the opposite ).

有部分原因，可以理解，是利益：枪支管制和持枪权利牵涉到了一些人们最珍视的价值，包括公众安全、自卫权、正当防卫权、隐私权和财产权。有部分原因是仅仅出于恐惧：很多人相信他们被暴力侵害的风险正在提高（虽然数据显示并非如此）。

And part of the reason is the trend in American politics over the last century: government has imposed itself so broadly that many issues are now winner-take-all, and people are desperate to avoid being on the losing side.

还有部分原因是美国在过去一个世纪里的政治潮流：政府管控范围如此之广，以致于很多事情都是赢家通吃，所以人们竭力避免站在输家那一边。

Those factors, along with the muddled complexity of gun research, should encourage more civil, open-minded, and respectful debate about gun laws, not to mention greater modesty about what policy can accomplish. Unfortunately, the opposite is happening. There's a lot of Red team/Blue team, "my side is smart and caring/your side is stupid and cruel" bile.

这些因素加上枪支研究的错综复杂，本应促使有关枪支法规的辩论更文明、更开放、更尊重他人，更不用说对于政策所能达到的效果应持有更谦虚的态度。不幸的是，现在的情况完全相反。到处都是红蓝对决，还有“我方聪明有爱心，你方愚蠢且残忍”的怒气。

Adding further fuel to this angry fire is the simple fact that people who dislike guns usually also dislike—and want to stick it to—people who like guns, and vice versa. And that's a serious threat to American society, too.

一个火上浇油的简单事实是，不喜欢枪的人通常也不喜欢爱枪的人，而且态度坚定，反之亦然。这对美国社会也是一个严重威胁。

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