Stat-Spotting. Joel Best
B1Statistical Benchmarks
When interpreting social statistics, it helps to have a rough sense of scale. Just a few benchmark numbers can give us a mental context for assessing other figures we encounter. For example, when thinking about American society, it helps to know that:
The U.S. population is something over 300 million (about 312 million in 2011).
Each year, about 4 million babies are born in the United States (the 2011 total was 3,953,593).1 This is a surprisingly useful bit of information, particularly for thinking about young people. How many first graders are there? About 4 million. How many Americans under age 18? Roughly 4 million × 18, or 72 million. Young people are about evenly divided by sex, so we can calculate that there are around 2 million 10-year-old girls, and so on.
About 2.5 million Americans die each year (there were 2,513,171 deaths recorded in 2011). Roughly one in four people dies of heart disease (23.7 percent in 2011), and cancer kills nearly as many, so that about half (1,171,652 deaths in 2011, or 46.6 percent) die of either heart disease or cancer. In comparison, some heavily publicized causes of death are much less common: for instance, traffic accidents killed roughly 35,000 people in 2011, breast cancer 41,000, suicide 38,000, homicide 16,000, and HIV/AIDS 8,000. That is, each of these causes accounted for less than 2 percent of all deaths.2
Statistics about race and ethnicity are complicated because these categories have no precise meaning. In general, however, people who identify themselves as blacks or African Americans account for just about 13 percent of the population—about one person in eight. (Remembering that the overall population is more than 300 million, we can figure that there are about 40 million black Americans: 300 million ÷ 8 = 37.5 million.) Slightly more—over 16 percent, or about one in six—identify themselves as Hispanic or Latino. But people cannot be divided neatly into racial or ethnic categories. Most government statistics treat Hispanic as an ethnic rather than a racial category, because Hispanics may consider themselves members of various races. Thus, in a 2007 press release announcing that “minorities” now accounted for one-third of the U.S. population, the census bureau announced that “the non-Hispanic, single-race white population [is] 66 percent of the total population.”3 Note the awkward wording: “non-Hispanic” is used because some people who classify their ethnicity as Hispanic also list their race as white; “single-race” because some people report mixed ancestry (such as having an American Indian ancestor). In short, the bureau is classifying as minority-group members some people who may consider themselves white. No single, authoritative method exists for classifying race and ethnicity. Still, a rough sense of the ethnic and racial makeup of the U.S. population can be useful.
Having this small set of basic statistical benchmarks for the overall population can help us place the numbers we hear in context. Sometimes, when we compare a statistic to these benchmarks, alarm bells may ring because a number seems improbably large or small. For instance, all other things being equal, we might expect blacks to account for about one-eighth of people in various circumstances: one-eighth of college graduates, one-eighth of prison inmates, and so on. If we learn that the actual proportion of blacks in some group is higher or lower, that information might tell us something about the importance of race in that category.
It isn’t necessary to memorize all of these figures. They are readily available. One of the most useful sources for basic statistics—just crammed full of official figures—is the annual Statistical Abstract of the United States. It is accessible online, and most libraries have a printed copy.4 Whether you can remember these basic numbers or whether you need to look them up, they can help you critically evaluate new statistics. We will have occasion to use these benchmarks (and we will identify a couple of others) later in this book.
| LOOK FORNumbers inconsistent with benchmark figures |
EXAMPLE: BATTERING DEATHS
A Web site claims that “more than four million women are battered to death by their husbands or boyfriends each year.”5 Right away, our benchmarks help us recognize that this number can’t be correct. With only about 16,000 homicides annually, there is no chance that there could be 4 million women killed in battering incidents. In fact, 4 million exceeds the nation’s annual 2.4 million death toll from all causes. We have no way of knowing what led the creator of the Web site to make this error, but there can be no doubt that this number is simply wrong.
Although this particular figure is clearly outlandish, I have seen it repeated on a second Web site. Statistics–both good and bad–tend to be repeated. People assume that numbers must be facts; they tell themselves that somebody must have calculated the figures, and they don’t feel obliged to check them, even against the most obvious benchmarks. For example, neither whoever created the 4-million-battering-deaths statistic nor the people who repeated that figure thought to ask: “Does this number for battering deaths exceed the total number of deaths from all causes?” Instead, folks feel free to repeat what they understand to be factual information. As a result, bad numbers often take on a life of their own: they continue being repeated, even after they have been thoroughly debunked. This is particularly true in the Internet age, when it is so easy to circulate information. A bad statistic is harder to kill than a vampire.
B2Severity and Frequency
In addition to having our small set of statistical benchmarks, it is useful to keep in mind one rule of thumb: in general, the worse things are, the less common they are.
Consider child abuse and neglect. Cases of neglect far outnumber cases of physical abuse, and only a small fraction of cases of physical abuse involve fatal injuries. Now, one can argue that every case of child abuse and neglect is bad, but most people would probably agree that being beaten to death is worse than, say, not having clean clothes to wear to school.
Or take crime. In 2011, there were about 700,000 motor vehicles stolen, but fewer than 15,000 murders.6 Stealing a car and killing someone are both bad, but almost everyone thinks that murder is worse than car theft.
Most social problems display this pattern: there are lots of less serious cases, and relatively few very serious ones. This point is important because media coverage and other claims about social problems often feature disturbing typifying examples: that is, they use dramatic cases to illustrate the problem. Usually these examples are atrocity stories, chosen precisely because they are frightening and upsetting. But this means they usually aren’t typical: most instances of the problem are less troubling than the example. Still, it is easy to couple a terrible example to a statistic about the problem’s scope: for instance, a report of an underage college student who died from acute alcohol poisoning (a terrible but rare event) might be linked to an estimate of the number of underage college students who drink (doubtless a big number).7 The implication is that drinking on campus is a lethal problem, although, of course, the vast majority of student drinkers will survive their college years.
| LOOK FORDramatic examples coupled to big numbers |
EXAMPLE: THE INCIDENCE OF BEING INTERSEX
A person’s sex–male or female–strikes most people as the most fundamental basis for categorizing people. Classification usually occurs at the moment of birth (if not earlier, thanks to ultrasound imagery): “It’s a girl!” or “It’s a boy!” This seems so obvious and natural that most of us rarely give it a thought.
Still, there are babies who don’t fit neatly into the standard male/female framework. Some babies have ambiguous genitalia; they can be recognized as hermaphrodites at birth. Others have less visible conditions that may take years to be recognized. People with androgen insensitivity syndrome, for instance, have the XY chromosomes found in males, but because their cells do not respond to testosterone, they develop female genitalia; the condition is usually not discovered until puberty. There are several such conditions, and people with any of them may be categorized as intersex.
Some