A fun thing about making predictions is ultimately finding out how wrong you were, and why. The chart below depicts the actual growth in charter school enrollment from 2000 to 2011, presented in Richard Buddin’s paper “The Impact of Charter Schools on Public and Private School Enrollments.” Now, as the old investment ads exhorted “past performance is no guarantee of future results.” But such a definitive pattern cried out for a regression fit. The dashed blue line in the chart below represents the “predicted” growth of Charter schools since 2011 (which I calculated three years ago from the 2000‐​to‐​2011 data). But how good was the prediction? As a test, I have plotted the actual data for 2012 to 2015 as red dots, using this and this as sources.

Well. Not bad. The accelerating growth in charter school enrollment could be excellent news for children and families–expanding the breadth of their educational options. Or (in the long term) it might reduce the variety of educational choices if charters become re‐​regulated (and thus homogenized) after having “eaten” a substantial number of diverse and much freer private schools. As Richard Buddin showed, charter schools are drawing students away from the freer independent school sector. And as the news routinely informs us, there are regular efforts to pile regulations onto charters to make them behave more like conventional state‐​run schools. In 2011, I raised the concern that this cycle could reduce educational liberty.

Two things are likely to happen over time: more private schools will be forced by economic expediency to convert to charter status as the number of competing charter schools grows, and the charter law is very likely to accrete regulation as charters enroll a larger share of the total student population. After all, the conventional U.S. public schools of the mid‐​to‐​late 1800s generally had more parental power and more autonomy than do typical charter schools today, but they have succumb to ever more extensive and more centralized regulation. If charter public schools follow the pattern set by conventional public schools, and if private schools continue to convert to charter status, what will be the end result? We could well see a heavily regulated state education monopoly that enjoys not a 90 percent market share, as it does now, but a 95 or even 99 percent market share. The end point would be worse than the situation we have today. While it is possible that charter schools will not accrete regulation like other public schools have as they begin to enroll a larger share of students, there is no reason to be hopeful in that regard.

With attempts to regulate charter schools more like state‐​run district schools continuing to this day, reasons for hopefulness remain scarce.

This, admittedly is a long‐​run concern. And as Keynes observed, “In the long‐​run, we’re all dead.” While that is literally true of any given generation, policy must be made with a view to functioning well not simply for us, now, but also for subsequent generations, decades hence. Having spent years studying the history of education systems, it’s hard not to be concerned with the long‐​run.