Carnoy and Rothstein (2013) compared US performance with Korean, Finland and Canada on the PISA 2009, given to 15-year-olds. All three of these countries generally score about 1/3 of a standard deviation better than the US in reading and math on international tests; Arne Duncan refers to these three countries as the three “consistent high-performers” (Carnoy and Rothstein, 2013 p. 10). In the PISA 2009 reading test, Korea had the highest score of all OECD countries (539), Finland was second highest (536) and Canada third (524). American students scored 500, 33 points behind the average of 533 for the three top countries.
A larger percentage of students in the US live in poverty, as compared to the top-scoring countries, and poverty level is consistently associated with school performance. Carnoy and Rothstein attempted to control for this.
They calculated that if the US had the same social class distribution as the average of the top three countries, the average US reading score on the PISA would be 518 (Cornoy and Rothstein, table 3A, p. 13). Social class (poverty) thus accounts for about half the reading gap, as measured by the PISA. Carnoy and Rothstein also concluded that social class accounts for a about a third or more of the math gap table 1B, p. 14).
Carnoy and Rothstein point out that they may have underestimated American students’ scores. They note that the US has a higher percentage of high poverty students enrolled in schools that have high concentrations of high poverty students, which also depresses academic achievement.
This data suggests that dealing with poverty, at least protecting children from some of the effects of poverty, will have a strong impact on achievement.
From Carnoy, M. and Rothstein, R. 2013, What do International Tests Really Show Us about U.S. Student Performance. Washington DC: Economic Policy Institute, p. 82. http://www.epi.org/).