Beyond Results: What Makes the Difference Between Argentina, Chile and Mexico in PISA 2009?

Considerable effort has been exercised in the construction of school achievement tests that provide international comparability of results. One of the most widely accepted studies for international comparison of student achievement is PISA. Argentina, Chile and Mexico mean score in language was quite similar in PISA 2000. However, a statistically significant gap developed during the decade, resulting in Chile and Mexico outperforming Argentina by some 50 and 30 points, respectively, in PISA 2009, and is the issue that motivates the research. This paper represents an attempt to develop some answers to the question of what makes the difference. Potential factors of policy interest explaining the gap in language test score between these countries are introduced through a linear model in which the relative effect of personal attributes of the student, relevant characteristics of his/her family and public/private school control are treated as covariates. The Oaxaca-Blinder decomposition technique is then applied and allows us to explain the mean gap between these three countries in PISA 2009 reading test scores in terms of coefficient and characteristics effects. Preliminary results suggested that compared to Argentina, Chile performed better in both, coefficient and characteristics dimensions, and 66% of the 50 point gap was associated with coefficient effects. The Mexico-Argentina 23 point gap resulted from the former’s hefty coefficient effects overcompensating for its relatively poorer characteristics.