Academic Legal Writing - Eugene Volokh [98]
But you can't just say “10% of all X's account for 25% of all Y's” in order to support the claim that those 10% have a disproportionate propensity to be Y. Such an inference is not sound, because these numbers can easily be reached even if everyone's propensity is equal.
J. A Source–Checking Exercise
The mistakes described above may seem obvious; but it's remarkably easy to make them. You can learn to avoid these mistakes by trying to spot them in others' articles, for example when you're cite-checking an article for your law journal. Start with the following exercise, drawn entirely from real articles. Do it yourself, and then check your conclusions against the answers on p. 366.
I'll begin with a paragraph from a student article in a Top 5 law review. Critically read it; assume that you are considering relying on it in an article you're writing, and are checking the original sources to make sure you won't embarrass yourself. I first noticed this article when a law professor relied on it in a talk he gave and in an article he wrote.
There are at least seven errors, of varying importance, in this excerpt. Go through the sources—source A and the other sources on which it relies—and try to find these errors.
The student article:
Proponents of manufacturers' liability further argue that handguns are almost useless for self-protection: a handgun is six times more likely to be used to kill a friend or relative than to repel a burglar, and a person who uses a handgun in self-defense is eight times more likely to be killed than one who quietly acquiesces. [Footnote cites source A.]
Source A (which was indeed written by a proponent of manufacturers' liability, so no need to check that), quoted in relevant part:
The handgun is of almost no utility in defending one's home against burglars. A Case Western Reserve University study showed that a handgun brought into the home for the purposes of self-protection is six times more likely to kill a relative or acquaintance than to repel a burglar. [Footnote cites source B.] .... The handgun is also of questionable utility in protecting against robbery, mugging or assault .... The element of surprise the robber has over his victim makes handguns ineffective against robbery .... A survey of Chicago robberies in 1975 revealed that, of those victims taking no resistance measures, the probability of death was 7.67 per 1000 robbery incidents, while the death rate among those taking self-protection measures was 64.29 per 1000 robbery incidents. [Footnote cites source C.] The victim was 8 times more likely to be killed when using a self-protective measure than not!
Although handguns possess little or no utility as self-protection devices, some may have a socially acceptable value when properly marketed under restricted guidelines [such as to the police].
Source B (the Case Western study), quoted in relevant part:
During the period surveyed in this study [1958–73 in Cuyahoga County, Ohio], only 23 burglars, robbers or intruders who were not relatives or acquaintances were killed by guns in the hands of persons who were protecting their homes. During this same interval, six times as many fatal firearm accidents occurred in the home.
Source C, the Chicago robbery study, quoted in relevant part:
Of those victims taking no resistance measures, the probability of death was 7.67 per 1000 robbery incidents, while the death rate among those taking self-protection measures was 64.29 per 1000 robbery incidents.
K. Summary
1. Find the original sources, rather than trusting what intermediate sources say about them. Don't rely on what a case, an