This past October, the Organization for Economic Cooperation and Development (OECD) released the first results from its survey of adult skills, OECD Skills Outlook 2013 . It presents more evidence that the United States is lagging behind other economically developed nations in building a quantitatively literate workforce. A rich source of data, the report is unusual in its focus on the numerical skills of adults, covering ages 16 through 65, and on its parallel investigations of literacy and "problem solving in technology-rich environments." Intriguingly, its data suggest that—although their numerical skills rank near the bottom—U.S. workers consider the numerical demands of their work and their ability to handle those demands to be greater than do workers in most other developed countries.
The OECD measured numerical proficiency at five levels:
1. Able to perform basic calculations in common, concrete situations.
2. Can identify and act on mathematical information in a common context.
3. Can identify and act on mathematical information in an unfamiliar or complex context.
4. Can perform multi-step tasks and work with a broad range of mathematical information in unfamiliar or complex contexts.
5. Can understand complex mathematical or statistical ideas and integrate multiple types of mathematical information where interpretation is required.
As an illustration of a task at level 3 (from the Reader’s Companion to the report [2, p. 30]): In 2005, the Swedish government closed its Barsebäck nuclear power plant, which was generating 3,572 GWh (Gigawatt hours) of power per year. Given that a wind power station generates about 6,000 MWh (Megawatt hours) of power per year, that 1 MWh = 1,000,000 Wh (Watt hours), and 1 GWh = 1,000,000,000 Wh, how many wind power stations would be needed to replace the Barsebäck plant?
Now the discouraging news. Only just over a third, 34.4%, of U.S. adults were capable of solving such a problem. In many OECD countries, over half the working age population was numerate at level 3 or above, including Austria (50.8%), the Czech Republic (51.9%), Finland (57.8%), Japan (62.5%), Norway (54.8%), the Slovak Republic (53.7%), and Sweden (56.6%). Germany came in just under at 49.1%. South Korea, at 41.4%, suffered from the fact that many of its older workers, especially those over 45, have skills that are far below those of younger Koreans. Other countries in which less than 40% of the population reached level 3 include Poland (38.9%), France (37.3%), and Ireland (36.4%). Only Italy (28.9%) and Spain (28.6%) came in lower than the United States. [1, Table A2.5, p. 262]
While the top 5% of U.S. adults are capable of working at level 4, the scores at the 95th percentile in the United States were well below those in most other OECD countries. The exceptions were France, Ireland, Italy, South Korea (again the unequal opportunity effect for older workers), Poland, and Spain. Only Finland had more than 2% of the adult population capable of working at level 5. In the United States, 0.7% of the adult population was capable of answering questions at level 5. [1, Table A2.8, p. 266]
The OECD data also reveal that the weakness of U.S. adults is not a recent phenomenon. The report separates numeracy skill levels by age decade: 16–24, 25–34, 35–44, 45–54, and 55–65. The United States is near the bottom of every age cohort, though it stayed above Italy and Spain and managed to climb above France and Ireland for adults 45 and older and above Poland and South Korea for adults 55 and older. [1, Table A3.2 (N), p. 272]
Given the low marks on numerical ability, it is interesting that when U.S. workers were asked whether they need to use their numeracy skills at work, the percentages were near the top of the OECD list. All of the following comparisons are for workers in the top 25% in terms of numeracy level. In the United States, 28.8% of these workers said that they need to use their numeracy skills frequently, as opposed to 28.0% in Finland, 26.7% in Germany, and only 17.7% in Japan. Only the Czech Republic at 30.0% and the Slovak Republic at 29.4% reported higher rates of frequent use of numerical skills. [1, Table A4.3, p. 303]
In addition, U.S. workers are more inclined to consider their numeracy skills to over qualify them for the requirements of their job. In the United States, 9.4% of workers considered their numeracy skills greater than the requirements of their job. In Italy, it was 12.6%; in Spain, 15.8%. In contrast, only 7.9% of the workers in Japan and 7.0% in Finland considered their numeracy skills to be greater than the demands of their job. [1, Table A4.25, p. 358] Across the OECD countries, there is a strong negative correlation between numerical ability and the perception of how well one has mastered the numerical skills required for one’s work.
That should be the most troubling aspect of this study.
 OECD (2013), OECD Skills Outlook 2013: First Results from the Survey of Adult Skills, OECD Publishing. http://dx.doi.org/10.1787/9789264204256-en
 OECD (2013), The Survey of Adult Skills: Reader’s Companion, OECD Publishing.
 The OECD countries in the survey were Australia, Austria, Czech Republic, Denmark, Estonia, Finland, France, Germany, Ireland, Italy, Japan, Korea, Netherlands, Norway, Poland, Slovak Republic, Spain, Sweden, United States, and three subnational entities: Flanders (Belgium), England (UK), and Northern Ireland (UK). Some data are also presented for Cyprus and the Russian Federation.