PISA test scores are aimed mainly at the evaluation of student knowledge at primary and secondary level in the fields of reading, mathematics and science. The assessment of knowledge in a particular field is subdivided into six different proficiency levels, ranging from 1 to 6. For instance, students at the 1st reading proficiency level are characterized by innate recognition of simple ideas reinforced in the text while students at the 6th reading proficiency level are characterized by a full capability of making multiple inferences, comparisons and contrasts and integrating the ideas presented in the text into a coherent conceptual framework of abstract ideas, sound evaluation and reflection. While 98.6 percent of OECD students can perform reading tasks at level 1, only 1.1 percent of students across OECD countries can perform reading tasks at the highest proficiency level. In addition, 28.4 percent of students in OECD countries exceeded the 4th (mid-range) reading proficiency level.
The reading scale has been further divided in reading continuous and non-continuous texts. However, the evidence suggest no systematic difference in reading scores between the two fields. Countries with the highest performance, measured as mean score, in reading rank are Korea (89.8 percent), Finland (89.3 percent) and Canada (87.3 percent). Countries with the largest student populations such as United States, United Kingdom and France were ranked in the upper-middle range while percent, and Israel (79 percent), Luxembourg (78.6 percent) and Austria (78.3 percent) are the lowest-ranking high-income countries on the reading scale in the 2009 PISA assessment. In the field of mathematics, 8 percent of students in OECD countries perform below level 1, 31.4 percent of students can perform mathematical tasks at 4th (mid-range) proficiency level while 3.1 percent of students perform at the highest proficiency level. In the country distribution, the percentage of students in the 6th proficiency level is the highest in Korea and Switzerland (8 percent), Japan, Belgium and New Zealand (5 percent). In a regional distribution, more than 25 percent of students in Shanghai perform at the highest level of mathematical proficiency. The proportion of students in the 6th proficiency level is very high in Singapore, Chinese Taipei and Hong Kong - 15.6 percent, 11.3 percent and 10.8 percent respectively. In addition, performance disparity in mathematics varied significantly across countries. Less than 1 percent of students in Mexico, Chile, Greece and Ireland reached 6th proficiency level A brief overview of the main empirical findings suggests a rather rigorous disparities in country ranking and performance.
The assessment of student performance in science is similar to the distribution of mean scores in the field of mathematics. About 5 percent of students perform below 1st proficiency level. In addition, only 29.4 percent of the students in OECD countries is proficient at 4th (mid-range) proficiency level in science while an average 1.1 percent of students in OECD countries can perform at the highest level of scientific literacy. In addition, the percentage of students below the lowest level of scientific proficiency is highly negatively correlated with country ranking since the proportion of students below the 1st level is the lowest in Finland (8.3 percent), Korea (6.3 percent), Estonia (8.3 percent) and Canada (9.6). Higher country ranking would thus indicate a lower proportion of students below the 1st proficiency level. All of the aforementioned countries ranked in the highest 10 percent of the distribution. If Shanghai, Hong Kong, Macao and Taipei were independent countries, their respective ranking in the field of scientific literacy would be in the top 10 percent of the distribution.
The empirical data on the distribution of mean scores in reading, mathematics and science are highly relevant to the measurement of human capital since the impact of mean scores on economic growth would differ to the certain extent from other measures of human capital. Recent attempts to capture the effect of human capital on economic growth were aimed at the definition of human capital as total years of primary, secondary and tertiary schooling. For instance, Robert Barro and Jong Wha Lee have collected disaggregated data on the total years of schooling for 146 countries between 1950 and 2005 at five-year intervals (link). The empirical evidence from the country panel suggests a strong linkage between schooling and long-run economic growth and institutional country features (link). In addition, Barro and Lee estimated the implicit return from an additional year of schooling ranging from 5 percent to 12 percent.
Gary Becker (link) and Richard Posner (link) recently discussed the 2009 PISA findings and the impact of cultural, genetic and demographic disparities on mean test scores in the United States. United States ranked in the middle of the mean score distribution. The rank of the United States (17th out of 79 countries) is above average in reading and average rank in mathematics (31st out of 79 countries) and science (23rd out of 79 countries). As Becker and Posner indicate, the relative performance of the United States should be evaluated with the consideration of cultural and demographic differences since the mean score of White and Asian students is significantly higher than the mean score of African American and Hispanic students. Disparities in mean scores between different demographic groups are typical in largely heterogenous populations. In Belgium, the regional disparity in mean scores between French and Flemish communities is even more striking. While the mean score in mathematics in 2006 in Flemish community had beenabove the OECD average, the mean score in mathematics of students in French community had been 18.56 points below the OECD average while the mean score of students in Flemish community had been 30 points above the OECD average. In 2009, such a relative difference would place French community in the rank of Italy, Portugal and Spain. On the other hand, student performance in Flemish-speaking community would reach the rank of Canada, Switzerland and Japan.
In the U.S, the demographic disparities in mean scores in reading, mathematics and science do not reflect the quality of the American education system. While the overall quality of the public and private American high school education system raised considerable concerns in previous performance of U.S. students in international mathematics and science ranking, the ranking of U.S. universities in science, mathematics and social sciences is the highest in the world. The output U.S. universities resulted in the highest number of Nobel laureates in physics, chemistry, medicine and economics as well as into cutting-edge accomplishments in R&D and technology. The emphasis on creativity and innovative thinking embodied in the American education system has enabled the United States to emerge as a world leader in technology, R&D, innovation and entrepreneurship.
The openness of the U.S. education system to international students, ideas and creative thinking could account for the remarkable achievements and academic quality of top American universities. On the other hand, poor teacher quality in American high school system is detrimental to the reading and quantitative literacy of American high school graduates, as a consequence of what Becker calls "teaching-to-the-test" syndrom where many public school teachers teach students topics not relevant to the command of knowledge but to the tests since test scores presumably determine teacher pay. Eric Hanushek of Hoover Institution recently found (link) that replacing bottom 5-8 percent of high school teachers with average teachers could near the United States on top of the international mathematics and science ranking. In addition, the measure is worth $100 trillion according to Hanushek (2010).
In the international perspective, student performance has been viewed as a significant determinant of the difference in cross-country economic performance. Recent paper by Atherton, Appleton and Bleaney (2010) found that higher mean test scores in mathematics, reading and science significantly improve per capita GDP. The authors showed that holding per capita income constant, average years of schooling is less important than mean test scores in predicting the economic growth. The 2009 PISA study highlighted the relationship between international test scores and economic growth. The evidence suggests almost non-existent correlation between reading performance and GDP per capita and cumulative education expenditure. The evidence simply suggests that socioeconomic variables matter more for reading performance than simple and often inconclusive aggregate indicators. In analysing the impact of various social and economic variables on reading performance, the results suggest a high correlation between parents' education and children's reading performance. For instance, 1 percentage point increase in the percentage of the population aged 35-44 with tertiary education returns 1.36 point increase in average reading performance where parents' education accounts for 44 percent of the variation in children's reading performance. The impact is shown in the following graph.
Parents' education and student reading performance
A brief look also reveals another striking implication: cross-country reading performance is strongly affected by social and cultural status of the child's parents. A simple estimate of the relationship between reading performance and socio-economic status suggests that 1 percentage point increase in the share of students with very low social, cultural and economic status tends to decrease the average reading score by 1.13 points. Hence, social, economic and cultural status explains about 46 percent of the variation in student reading performance.
A considerable improvement of primary and secondary education system is vitally essential to the long-run economic growth. International test scores are an important method of evaluating international disparities in student performance and the subsequent impact on economic growth. Modern knowledge-driven economy requires not only intelligence, attentiveness but also comprehensive, integrated and developed social skills. Low reading, mathematics and science performance is generally attributed to student's low social, cultural and economic status. Genetic, cultural and socioeconomic variables, rather than education expenditure and GDP per capita, tend to play a major role in early childhood development as a basis of future student performance.
The economic and social future of countries requires considerable investment in children and student. Professor James Heckman of the University of Chicago brilliantly argued in Heckman equation (link) why the most gainful benefit of early childhood development is increased social productivity, greater motivation and developmental stimulation that every child needs. Our society should be not neglect an indisputable fact that early childhood development is a major determinant of student performance which sets the conditions for future advantage in school, college, career and life in general. Without these essential measures, student performance would suffer heavily from the spread of crime, teenage violence and high dropout rates.
The evidence from the 2009 PISA study suggests that higher quality of the education system is a necessary condition for higher test scores in reading, mathematics and science. As the evidence suggests, that the quality of human capital is strongly associated with higher standard of living. Without a prudent step towards improving developmental stimulation of students, considerably low student performance may seriously harm the prospects of future generations.