The standard concern about such a picture is that it might not represent a causal relationship because other factors may be more important and are simply correlated with achievement. We have investigated other possible explanations in depth (Hanushek and Woessmann 2015), and—while it is impossible to remove all doubt—we show a credible case that lifting achievement has a powerful impact on growth. We find, for example, that achievement tests up to the early 1980s predict subsequent growth (which rules out simple reverse causation) and that greater spending (which may come from faster growth) does not consistently raise achievement. Furthermore, if we use only part of the achievement variation that emerged from good institutions of the school system, such as strong accountability measures or more school choice, we find the same link to faster growth, which rules out the notion that higher achievement simply captures omitted factors from outside the school system. And we find that countries with increased achievement over time have subsequently shown increased growth rates, thus dealing with potential omitted cultural or institutional factors.
The world picture of education
Tracking success in the area of education has historically been difficult. International achievement tests were first developed in the 1960s—and all rich countries are now participating regularly—but a majority of poor countries have never participated. A series of parallel regional tests have been developed, but they lack direct linkages to the broader-scale international assessments. And many countries, including the two most populace, have not produced student outcome data in a consistent manner.
In our most recent research, we bring the different international and regional assessments of student achievement together (Gust, Hanushek, and Woessmann, forthcoming). While some uncertainty remains, we characterize the world pattern of achievement and skills with sufficient accuracy to permit addressing the state of the world with respect to the SDGs.
We define basic skills as the skills necessary to participate productively in modern economies. Pragmatically, we assume these to be represented by mastering at least the lowest of the six skill levels of the international PISA test—that is, PISA Level 1 skills. Students at this level are able to carry out obvious routine procedures according to direct instructions, but they cannot draw direct inferences or reliably employ basic conventions to solve simple problems involving whole numbers. Such basic skills are a key foundation not only for participating in modern societies, but also for engaging in lifelong learning as is necessary in an ever changing world.
The picture that emerges from our analysis is disturbing. Two-thirds or more of the world’s young people fail to reach the minimum skill levels required to compete in the international economy. These deficits are found worldwide, but are most severe in the poorest countries—as shown in Chart 2.