Quantitative Literacy is one of those things about which we say “I know it when I see it”, but is difficult to describe precisely and concisely. It includes numeracy (an understanding of numbers and magnitude); some geometric, algebraic and algorithmic skills; some problem solving ability; an understanding of probability and statistics; and the ability to quickly capture information, summarize it, and make a decision.

The working definition I find most convenient is the following, extracted from the bylaws of the MAA's SIGMAA on Quantitative Literacy. (There are alternatives provided in the various essays included in this volume and in related works.)

Quantitative literacy (QL) can be described as the ability to adequately use elementary mathematical tools to interpret and manipulate quantitative data and ideas that arise in individuals' private, civic, and work lives. As with reading and writing literacy, quantitative literacy is a habit of mind that is best formed by exposure in many contexts.

As mathematicians, it is very tempting to say that being quantitatively literate is equivalent to being more proficient at mathematics, and therefore the solution to developing quantitatively literate citizens is to have them study more mathematics. But this is inherently a poor solution since mathematics is fundamentally about developing and understanding deeper abstractions and connections. Mathematics uses many tools and techniques that, to put it bluntly, do not have much value in the daily world of our fellow citizens.