In the new issue of Harper’s, there is a footnote in the main cover story that nicely sums up what a barrier to communication innumeracy can be:
And to say there is room for academic improvement at the school [The High School for Health Careers and Sciences in Manhattan] is a vast understatement. Only 58 percent of its students graduate in four years. Of all graduates, 41 percent leave with a full “Regents diploma,” which is conferred if a student scores 65 percent or higher on five subject-proficiency exams. A mere 3 percent of Health Career’s students graduate with an “advanced” diploma, which can be earned if they take three additional Regents exams and an increased credit load. The state average is 36 percent.
First of all, the state average what is 36 percent? Graduation rate? This would put ‘Health Career’ above average, but that’s neither here nor there, as it’s plausible (likely, even) that the average is so far below ceiling that the entirety of above average schools have ample room for improvement.
Maybe it’s ‘Regents diploma’ rate, instead, though I have no idea (and the article certainly hasn’t made it clear) whether ‘Regents diplomas’ are unique to this high school or a staple of New York state secondary education. Which is to say that I have no idea if there is a state average for “Regents diplomas” at all.
Or it could be “advanced” diplomas we’re talking about.
Consider, too, how the the percentages are presented. 58 percent of students graduate. Of these, 41 percent (i.e., 23 percent of the school’s students) get the “Regents diploma.” 3 percent of the students (i.e., 5.8 percent of those who graduate) get an “advanced” diploma. For good measure, throw in a 65 percent passing grade on a test, which adds no useful information at all, and maybe makes the passage even more confusing.
Of course, the fact that the reader has no idea what the last sentence of the footnote refers to and the fact that the writer casually switches from conditional to non-conditional percentages isn’t necessarily due to innumeracy. It could just be sloppy writing. At the very least, it reflects a cavalier attitude toward marshaling numbers in support of an argument. But is that any better than being innumerate? At best, such an attitude enables continued innumeracy in the reader. At worst, it fosters it.
Exercise: Show how the referents of the subject ‘it’ and object ‘it’ are resolved, thereby showing why, in context, the meaning of the clause ‘it fosters it’ is unambiguous.