Even in the midst of a near-monopoly education system, most parents are active participants in determining, or at least attempting to influence, where and how their children are educated.

Some parents investigate their options and decide to accept the district-run public school assigned to them. Others seek to escape the default public school by applying for transfers or magnet schools, relocating to other assignment districts or counties they believe will put their kids in better public schools, or – in counties such as Forsyth, Mecklenburg, Cumberland, and Wake that allow it – indicating a different choice than the one assigned to them.

Still other parents, dissatisfied with all their district-run options, decide to try a public charter school. Or they make the significant financial sacrifice of enrolling their children in private schools, or educating them at home.

[The school-choice movement, by the way, is not about introducing parental choice to education. As you see, it already exists. The problem is that it is unnecessarily and unwisely limited. Families of poor or modest means often lack the resources to move to a different public-school district or pay private-school tuition, for example. School-choice policies are designed to reduce the institutional and financial barriers for parents who believe these options would be best for their children.]

Parents make these decisions based on many variables. They include real or perceived differences in academic rigor and teacher quality, school safety and discipline, proximity and convenience, shared cultural or religious values, and extracurricular offerings.

I can say that when it came to selecting schools for my own boys, several of these factors came into play. They have been in both public and private schools over the course of their academic careers, as I was during my childhood.

One reason their mother and I eventually chose a private school for our boys is that it houses grades kindergarten through 12. While there are transitions from elementary to middle school, and then from middle school to high school, they occur within the same institution. For many students, avoiding an abrupt change of venue, surroundings, personnel, and community is an underappreciated benefit.

Private education is not the only way to avoid such abrupt changes. Many charter schools currently operate as K-8 institutions, and plan to add high-school grades over time. An increasing number of public-school districts are also reconsidering the rigid separation of elementary and middle school. One of them is Charlotte-Mecklenburg, which in 2010 closed several middle schools and combined their student populations with those of elementary schools. Baltimore, Philadelphia, Milwaukee, and New York City have been doing something similar for several years.

Are there educational benefits from expanding the use of K-8 public schools? A recent study by two education researchers suggests an answer in the affirmative. Martin West of Harvard University and Guido Schwerdt of the Ifo Institute for Economic Research in Germany examined student-performance data for Florida public schools from 2000-01 to 2008-09. Florida offered an interesting test case because some students proceed to middle schools in sixth grade and some in seventh grade, while others remain in K-8 schools.

Their study is complex and deserves a full reading. Here’s the key finding, however. Everything else being held equal, transferring to middle school results in large and lasting disadvantages for students. “After three years in middle school, students who entered in sixth grade score 0.23 standard deviations in math and 0.14 standard deviations in reading worse than we would have expected had they attended a K-8 school. After two years in a middle school, students who entered in seventh grade underperform by 0.31 standard deviations in math and 0.15 standard deviations in reading.”

To put this finding in perspective, students in sixth and seventh grade typically increase their math performance by 0.30 standard deviations per year and their reading performance by 0.25 standard deviations per year. In other words, the negative effects of the middle-school plunge represent several months worth of learning.

Interestingly, West and Schwerdt found a much-smaller effect when students move from middle to high school. The K-8 model might not be the right fit for every student, but Charlotte-Mecklenburg was wise to expand its use. Other districts should follow suit. Moreover, any public policies that expand the availability of K-8 options for parents – be they magnets, charters, or private schools – may well boost student success even if there aren’t big gains in the quality of the curriculum or teachers.

Choice and competition aren’t panaceas. But they certainly are useful tools for educational improvement.

Hood is president of the John Locke Foundation and author of Our Best Foot Forward: An Investment Plan for North Carolina’s Economic Recovery.