If you ask a charter school supporter why charter schools tend to exhibit inconsistency in their measured test-based impact, there’s a good chance they’ll talk about authorizing. That is, they will tell you that the quality of authorization laws and practices — the guidelines by which charters are granted, renewed and revoked — drives much and perhaps even most of the variation in the performance of charters relative to comparable district schools, and that strengthening these laws is the key to improving performance.

Accordingly, a recently-announced campaign by the National Association of Charter School Authorizers aims to step up the rate at which charter authorizers close “low-performing schools” and are more selective in allowing new schools to open. In addition, a recent CREDO study found (among other things) that charter middle and high schools’ performance during their first few years is more predictive of future performance than many people may have thought, thus lending support to the idea of opening and closing schools as an improvement strategy.

Below are a few quick points about the authorization issue, which lead up to a question about the relationship between selectivity and charter sector growth.

The reasonable expectation is that authorization matters, but its impact is moderate. Although there has been some research on authorizer type and related factors, there is, as yet, scant evidence as to the influence of authorization laws/practices on charter performance. In part, this is because such effects are difficult to examine empirically. However, without some kind of evidence, the “authorization theory” may seem a bit tautological: There are bad charters because authorizers allow bad charters to open, and fail to close them.

That said, the criteria and processes by which charters are granted/renewed almost certainly have a meaningful effect on performance, and this is an important area for policy research. On the other hand, it’s a big stretch to believe that these policies can explain a large share of the variation in charter effects. There’s a reasonable middle ground for speculation here: Authorization has an important but moderate impact, and, thus, improving these laws and practices is definitely worthwhile, but seems unlikely to alter radically the comparative performance landscape in the short- and medium-term (more on this below).

Strong authorization policies are a good idea regardless of the evidence. Just to be clear, even if future studies find no connection between improved authorization practices and outcomes, test-based or otherwise, it’s impossible to think of any credible argument against them. If you’re looking to open a new school (or you’re deciding whether or not to renew an existing one), there should be strong, well-defined criteria for being allowed to do so. Anything less serves nobody, regardless of their views on charter schools.

In theory, among the most effective approaches for improving the performance of larger charter sectors via authorization/ deauthorization might be closure with minimal replacement. Closing “low performing” schools, whether charter or regular public, is disruptive for students’ academic progress, as well as for communities (and identifying these schools is also a serious issue). Although students of closed schools typically end up dispersing into whatever schools are in their area, the “close bad schools, open good ones” approach in theory, can of course work out, so long as the replacements are sufficiently better.

In the charter school realm, there are a handful of models that have been shown to get fairly good results no matter where they operate. These schools tend to share certain features, including heavy private funding, massive extensions of school time, intensive tutoring programs and strong disciplinary policies. If an operator that employs this kind of approach is willing to open up shop in a given location, and has a stable flow of private money, letting them do so may be a pretty good bet (though there may be a limit on their ability to successfully replicate within a given area).

So, given the risks of closure, as well as the scarcity of proven models (and financial and human resources), one promising authorization-based approach may be to slowly and carefully shut down the schools that consistently fail to produce results, and/or only open new schools if they embody the handful of models mentioned above (while perhaps allowing a limited number of opportunities for promising new models).

Employing the “authorization theory” in this manner would of course be impractical in many places, since the supply of new schools would be insufficient to meet the demand of students from closed schools. Nevertheless, in theory, it might actually serve to dramatically improve aggregate charter sector performance, especially in states and districts where market share is already high. This leads us to the final point.

There may be a tension of sorts between improving charter school quality and expanding charter school market share. The idea of closure with minimal replacement would, of course, shrink charter market share in many places, as far fewer new schools would open than would be closed. Charter advocates’ vision, in contrast, is much less extreme – i.e., put simply, that authorizers should more selective in allowing new schools to open, and/or more aggressive in closing down low-performing schools. But even this approach would possibly, if not probably, slow charter school growth – i.e., fewer schools opening due to more stringent authorization practices, and, perhaps, more closing up shop.

In other words, the “authorization theory” may in fundamental respects work at cross-purposes with the effort to expand rapidly charter school market share.

Yet charter school proliferation is proceeding at a fast pace, and many advocates calling for stronger authorization and deauthorization are also lobbying hard for lifting charter school “caps” – the laws that limit (or do not limit) the number of charters that can be in force at any given time, or the rate at which new charters can be granted.

From this perspective, one wonders whether the priority here is rapidly improving charter school quality or rapidly growing charter school sectors. These two goals may not be particularly compatible. For example, the aforementioned CREDO study found that higher-performing CMOs expanded at a slower pace than lower-performing CMOs. Moreover, the few districts in which relative charter performance is strong overall tendto be those in which market share is relatively small.

This might reflect the common sense idea that opening good schools is difficult, error-prone and expensive, and really isn’t something that can be done consistently well at too quickly a pace. And there are signs that even the most aggressive charter advocates recognize this.

In short, then, improving authorization policies is a good idea, and the discussion above is not meant to imply that local charter sectors cannot improve and expand at the same time. But, at the very least, it’s a question worth asking. Perhaps one necessary side effect of better authorization is less authorization.