Ch. 1: Charter Schools and Student Achievement: A Review of the Evidence (HFR '08)

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December 2008
Julian Betts, Y. Emily Tang

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National charter school achievement is promising overall, but highly varied

A single generalization, like “on average, charter schools are at best slightly more effective than the schools their students would otherwise have attended,” can hide as much as it reveals. We learn a great deal more by asking how and why charter school effectiveness varies. In this chapter, Julian Betts and Y. Emily Tang show us that there is strong evidence that charter schools are outperforming other public schools in many ways. But their analysis of existing charter school outcome studies also indicates that:

• Charter school studies are highly varied in quality. The maxim caveat emptor (buyer beware) applies here: only about a third of all charter studies can be trusted to give a fair picture of whether students are better off in a charter school or not.
• High-quality studies are more likely than weaker studies to find positive charter school results on student learning, in both reading and math.
• Even high-quality studies show tremendous variability in results. Charter schools perform much better in some localities than in others. Elementary charter schools, in general, appear to outperform charter middle and high schools.

Variation in charter school results has been a source of criticism in the past, with some observers lamenting “mixed” results. Betts and Tang argue, however, that a high degree of variation in achievement outcomes is an entirely predictable and possibly even a desirable short-term product of charter schooling. Since innovation and experimentation rely on diverse strategies and some risk taking, both failures and successes are to be expected. Local variation, again with different results, is also a factor that needs to be taken into account. Some localities and local charter schools have a very good grip on what they’re trying to accomplish; others are hoping for the best.

In the long run, the success of the charter movement will depend on whether it is able to build on successes and abandon failures. To reinforce success and eliminate failure, we need to understand what explains these variations. A second generation of achievement research in these areas is urgently needed. What are the attributes of highly productive versus unproductive charter schools? What are more successful states and cities doing that others might replicate? What explains the apparent low performance of charter high schools and what can be done about it?