A study of international maths and science test results has found that the highest-scoring countries are those with the least inequality in test scores. It also found that countries perform even better when test scores are highly correlated with the number of books in the family home.
The paper uses test scores on fourth- and eighth-grade mathematics and science from the Trends in International Mathematics and Science Study (TIMSS) tests in the 1999 and 2007 to examine the magnitude and correlates of country differences in levels and dispersion in test scores. It relates test scores of students to measures of their background characteristics within each country and examines the link between the estimated association of characteristics with the country level and dispersion of test scores.
It found wide cross-country variation in the level and dispersion of test scores, but that countries with higher average scores also have lower inequality in test scores. The same pattern exists in both mathematics and science in fourth and eighth grades.
The paper also analyses the association of gender, immigrant status, and family background factors with test scores in eighth-grade mathematics for the whole sample of students. It found no difference in the results by gender for 2007, advantages from being born in the country and a large positive effect of larger numbers of books in the home and higher parent education.
The largest change between 1999 and 2007 was for females. In 1999, females did significantly worse on the eighth-grade maths test than males; but consistent with other studies that show females catching up with males in mathematical tests, there was no statistically significant gender difference in the 2007 data.
The biggest gain for females occurred in the lower parts of the test-score distribution and it declined less at the upper end of the test-score distribution. This pattern shows that the dispersion of test scores among females in the sample narrowed while the dispersion among males did not, contributing to the drop in the male advantage on the mathematical test scores.
The paper also found large cross-country differences in the relation between the background factors and test scores. In some countries, background contributes greatly to the variation in scores, whereas in others it has modest effects.
For example, it found large cross-country differences in the relation between family background measured by books in the household and students’ performance. In some countries, students with more books at home did a lot better in mathematics tests than students with fewer books in their home. In other countries, the number of books in the home had relatively weak effects on student test scores.
The paper analyses whether countries with smaller or larger background effects have higher/lower average test scores or greater/lesser within-country inequality in scores. It found that countries in which the number of books in the home is strongly related to individual student test scores tend to have higher average test results than countries in which the relationship between is weaker. There is also less dispersion between test scores in countries where books in the home is strongly related to individual student test scores, that is, less inequality in test results.
In contrast, countries where parents with higher education give greater advantages to their children in test scores do only a slightly better than countries where parental background is weakly related to test-score performance and there is little difference in terms of score dispersion.
These results suggest that differences in books at home have a larger impact on inequality in education compared to parents’ education. Since books in the household likely reflect various aspects of non-school educational resources, the results direct attention at policies that seek to increase resources for disadvantaged families that complement formal schooling.
Trevor Cobbold
Richard Freeman; Stephen Machin and Martina Viarengo, Variation in Educational Outcomes and Policies Across Countries and of Schools Within Countries, Working Paper No. 16293, National Bureau of Economic Research, Cambridge, Mass., August.