Early selection of students into different schools based by ability increases educational inequalities. It also tends to reduce average performance. These are the central conclusions of new research by Ludger Woessmann and Eric Hanushek, published in the March 2006 issue of the Economic Journal.
Many countries worry about the relative merits of a selective versus comprehensive school system. The resulting choices are surprisingly different: countries such as Austria, Germany and Hungary put students in different ability schools as early as age 10. In contrast, others including Canada, Sweden, the UK and the United States nowadays essentially keep their entire lower secondary school system comprehensive.
Parents and politicians alike would like to know whether putting students on different school tracks has consequences for the equity and efficiency of educational outcomes. This research provides evidence from international experiences across countries that early tracking increases educational inequality. While less clear, there is also a tendency for early tracking to reduce mean performance. So there does not appear to be an equity-efficiency trade-off.
Macro issues of institutional structure are extraordinarily difficult to evaluate within individual countries, largely because the variations in structure are almost certainly related to the characteristics of the families and schools choosing to follow an anomalous pattern.
To address these empirical complexities, the researchers use the variation in both the institutional structure of between-school tracking and student performance across countries to sort out the impacts of tracking.
In essence, they identify the effects of tracking by comparing differences in outcome between primary and secondary school across tracked and non-tracked systems. That is, they compare the level and distribution of performance of younger students (before tracking is introduced in any country) with those of older students (after some countries have started tracking) across countries with and without tracking, effectively controlling for any crosscountry variation that existed already in primary school. The existence of several large international assessment programs permits a consistent evaluation of student performance across a wide range of countries.
The analysis provides reasonably strong support for the ''disequalising'' effects of early tracking. Variation in performance, measured in a variety of ways, tends to increase across levels of schooling when a country employs early tracking. Although the evidence on the level of performance is more mixed, there is very little evidence that there are efficiency gains associated with this increased inequality.
From a policy perspective, it seems incumbent on those advocating early tracking in schools to identify the potential gains. This research suggests that countries lose in terms of the distribution of outcomes, and possibly also in levels of outcomes, by pursuing such policies.
''Does Educational Tracking Affect Performance and Inequality? Differences-in-differences Evidence across Countries '' by Eric Hanushek and Ludger Woessmann is published in the March 2006 issue of the Economic Journal.