BOSTON—THE GREATEST SIN that any Red Sox owner can commit is to allow a star player to move to New York. From Babe Ruth to Johnny Damon, these defections are greeted with howls of outrage from the fans and columnists of Red Sox Nation.

But the Sox aren’t the only ones who let talented Bostonians slip away to our rival on the Hudson. Over the past several years, Boston has quietly lost some of its top educators to the Big Apple. A little over three years ago, the founders of three nationally recognized Boston charter schools – Roxbury Preparatory Charter School, Academy of the Pacific Rim, and Boston Collegiate – helped to create an ambitious network of charter schools in New York and New Jersey. Last year, the head of City on a Hill Charter School, which has helped 100 percent of its graduates gain admission to college, moved to New York City to become Chancellor Joel Klein’s charter schools chief. And this fall, the founder of East Boston’s Excel Academy, which ranks among the state’s top five middle schools in eighth-grade math, is stepping down to explore new school reform opportunities in the New York metropolitan area.

For almost 15 years, Massachusetts in general and Boston in particular have been places where rising stars of education have come to build charter schools, offering students – mostly from poor neighborhoods – a superior education. But now these leaders are starting to leave, concluding that Boston is just not the place for them to realize their greatest aspirations. The city is approaching a state-mandated limit on the number of charter schools, and the broader environment has been at best tepid, and frequently hostile. Both Governor Deval Patrick and Mayor Thomas Menino have consistently opposed any expansion of charter schools – notwithstanding their high levels of student achievement, the large number of parents seeking to gain admission for their children, and the growing list of district schools that are failing to meet state performance standards.

Massachusetts has distinguished itself as one of the nation’s leaders in school reform, and an important part of that success story has been its charter schools. Now, after leading the field, Boston is losing some of its best players, raising fears that public education may suffer its own curse of the Bambino.

It is commonly understood that a great education is dependent on great teachers. What is less well appreciated is that leadership can be even more important. In the absence of great school leaders, it is difficult, if not impossible, to attract, support, and retain a high quality faculty. Schools need a rigorous and coherent curriculum, well-designed systems to support instruction across every classroom, and a powerful, schoolwide culture grounded in high expectations for everyone – students and staff alike. Putting these building blocks in place and ensuring they all work well together over time requires enlightened, effective leadership. And as much as there is a shortage of great teachers – especially in low-income communities – there is an even more acute shortage of great school leaders.

Much has been made over the years about the importance of attracting and keeping the best intellectual talent to sustain Massachusetts’ knowledge economy. The state spends millions of dollars in tax incentives, infrastructure development, and cash grants to bring technology companies to the Commonwealth. Most recently, the Patrick administration launched a billion-dollar investment fund to stimulate the biotechnology sector.

Recruiting and retaining the best technical and managerial talent is the only way knowledge-based companies can survive. Yet in public education – a knowledge business if there ever was one – talented educators and leaders are too often ignored. For Massachusetts, as for all states, the knowledge economy is the future. The jostling to succeed in it is well underway.

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Back in 1993, Massachusetts was one of the first states to adopt a law establishing charter schools, which are independently managed public schools. When the call went out for innovative educators willing to take a risk on an unproven experiment in school reform, a cadre of rising social entrepreneurs stepped forward. The schools that were formed in those first few years inspired charter founders across the country. And the excitement and hope they generated have borne fruit for our students: Boston’s top four non-exam high schools are charter schools, as are five of the top six middle schools.

Nevertheless, as the charter movement has taken off in other states and cities, our leadership position has waned. Last year, Massachusetts enrolled fewer than 2.5 percent of its public school students in charter schools, placing us 19th among the 41 states (including Washington, D.C.) that have enacted charter laws. And our rank is falling.

Half of the public schools in New Orleans are charters. One-quarter of the students in Washington, D.C., are now enrolled in charter schools.

The number of charters in Los Angeles has more than doubled over the past four years. Meanwhile, the charter share of Boston’s public school system is under 8 percent, with annual growth of only about 300 students.

Even that modest growth is about to come to an end as Boston approaches a statutory cap on charter school enrollment. Charter schools are given public funds based on the number of students they educate. But state law dictates that their overall funding not exceed 9 percent of the public school budget in their host districts. Springfield, Worcester, Lawrence, Lowell, and Holyoke are also bumping up against the cap.

This constraint limits access to the schools for students, but it also discourages the best charter school leaders. Every charter school founder understands the importance and challenge of creating and sustaining even one great school. For many of these entrepreneurs, however, one great school is not enough; they want to have a bigger impact on underserved children and communities – as well as on the broader system of public education. And to do that, under the current law, they have to go elsewhere.

Consider the case of Uncommon Schools, a nonprofit network of charter schools that was launched in 2005 as a collaborative venture involving the leaders of several high-performing charter schools. Among the original leadership team were four Boston educators: Brett Peiser of Boston Collegiate, Doug Lemov of Academy of the Pacific Rim, and John King and Evan Rudall of Roxbury Prep. This summer, Josh Phillips, the successor to King and Rudall at Roxbury Prep, left Boston to join his former colleagues at Uncommon Schools. (I serve on the board of directors of Uncommon Schools, on behalf of NewSchools Venture Fund, a nonprofit grant-making firm that has helped fund it.)

Uncommon Schools operates 11 charter schools in Brooklyn, upstate New York, and Newark. Over the next five years, Uncommon Schools plans to launch another 20 schools. Enrollment across all the Uncommon Schools campuses is now 2,000. Virtually all of these students are black or Latino and more than 80 percent come from low-income families. By 2020, Uncommon Schools hopes to be educating more than 10,000 such students.

John King, formerly of Roxbury Prep, oversees Excellence Academy, an all-boys elementary school in Bedford Stuyvesant that is part of Uncommon Schools. One-hundred percent of the Excellence fourth-grade class scored “proficient” or higher on New York’s state math assessment last spring – 20 points higher than the city average. Ninety-seven percent of the fourth-grade class reached proficiency in reading – a whopping 36 points above the city average.

Doug Lemov, formerly of Academy of the Pacific Rim, started True North Rochester Prep, another Uncommon school, in 2006. Last spring, 98 percent of its sixth-graders scored proficient or advanced on the state math exam – almost 20 percentage points above the state average.

Students at Williamsburg Collegiate in Brooklyn, an Uncommon Schools middle school started by Brett Peiser, posted a 100 percent proficiency rate in seventh-grade math, with 92 percent proficiency in English – more than 30 points above the city average in both subjects. Williamsburg Collegiate was ranked first out of more than 1,200 schools last year by the New York City Department of Education. These results should be no surprise to Bostonians, since Peiser’s first charter school, Boston Collegiate, boasts high school proficiency rates well over 80 percent – higher than all of the district’s open enrollment high schools.

“Given Boston Collegiate’s results, we were eager to build more schools based on the Collegiate model,” says Peiser. “We had over 1,000 families on our waiting list eager for a safe and academically rigorous public school option, but the political situation made creating more schools in Boston nearly impossible. While I had a strong commitment to public education in Boston, the opportunity in New York City was one I couldn’t pass up.”

We are fortunate that the successors to Rudall, King, Phillips, Peiser, and Lemov are themselves talented school leaders, so the schools they founded remain strong. But Boston is clearly worse off for their absence.

Charter school networks like Uncommon Schools are taking hold in an increasing number of urban districts. KIPP is perhaps the best known charter network, with 66 schools serving 16,000 low-income students in 19 states. Other notable examples include Aspire Public Schools, which operates 21 schools in California, and Achievement First, currently managing 15 schools in New York and Connecticut. By consistently replicating some of the most successful urban schools, these emerging charter networks are accelerating the pace of school improvement in underserved communities. And they are doing it by leveraging the impact of their leaders, whose influence would otherwise be confined to a single school.

The growing impact of charter networks on New York’s educational landscape is broader than the schools they operate. Uncommon Schools, Achievement First, and KIPP are together launching a new teacher preparation program that will provide intensive training for new educators and is grounded in effective, real-world classroom practice. In partnership with Hunter College, this program will develop new teachers for both New York’s charter schools and the city’s district schools.

Shouldn’t all this be happening here, too?

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The most obvious first step is to relax the constraints on charter school growth. State law should be changed to ensure that the most successful schools can expand and replicate without limit, and the arbitrary municipal caps on charters should be eliminated in the Commonwealth’s lowest performing school districts. Unfortunately, neither of these proposals was included in the governor’s recent 50-point education reform agenda.

Our political and educational leaders also need to ensure that this is a place where charters can prosper. That means investing in the incubation of new schools and the expansion of successful ones, broadening and strengthening the pipeline of talented educators for both charter and district schools, creatively using charters and performance contracts to help restructure or turn around failing schools, and opening up public school buildings to high quality charter operators.

In Philadelphia, the school district has entered into a partnership with entrepreneurial school operators like Mastery Charter Schoolsand Victory Schools to turn around some of the city’s worst performing schools. In Louisiana, the state is collaborating with Teach For America, The New Teacher Project, and New Leader for New Schools to recruit and train the next generation of educators for New Orleans. In Chicago, the district has closed some of its failing schools and turned the buildings over to entrepreneurial school management organizations, such as the Academy for Urban School Leadership.

The urban districts that are leading the way in charter school growth have openly embraced charters and charter networks as essential parts of systemwide reform. Visionary district leaders like Joel Klein (New York City), Arne Duncan (Chicago), Paul Vallas (New Orleans), and Michelle Rhee (Washington, D.C.) believe that these independently managed public schools not only provide important new options for low-income families, but also help to give them the leverage they need to make long overdue changes inside their district-run schools and central bureaucracies.

“Our mission is to close the achievement gap,” says Evan Rudall, chief executive officer of Uncommon Schools and founder of Roxbury Prep.

“We can do this critical work at scale in New York and New Jersey because the states allow a greater number of charter schools and because we are proactively supported by local mayors and superintendents.”

Massachusetts continues to serve as a national model in education reform. Our state curriculum standards and assessments are considered to be among the very best. Policy innovations and investments in early childhood education, longer school days, and out-of-school programs are widely praised and increasingly copied. But no matter how promising these initiatives are, we will never have a world-class public education system without world-class school leaders.

Massachusetts is in competition with other states and countries for private investment dollars across numerous knowledge-based industries, and, it is true, we are currently in a strong position. According to the Milken Institute, the Commonwealth ranks first among all states for its science and technology assets. But we cannot afford to be complacent, as other states and emerging economies from around the globe redouble their efforts to overtake us. Remember what we learned in the 1980s, when Massachusetts’ computer industry collapsed in the face of competition from Silicon Valley and Japan; competitive advantage cannot be taken for granted.

Government subsidies may provide a sufficient incentive for some businesses to locate and grow here, but without a highly skilled workforce, we won’t be able to give away enough money to seal the deal. There is no substitute for a high-performing system of public education. Yet we are driving away the very people who are capable of contributing the most to this critical cause.

Losing an all-star like Pedro Martinez may be costly, but losing our best and brightest educators exacts a far higher price.

James A. Peyser is a partner with NewSchools Venture Fund, a nonprofit grant-making firm that supports education entrepreneurs, and is a member of the board of directors of Uncommon Schools, a nonprofit charter management organization. From 1999 to 2006, he served as chair of the Massachusetts Board of Education.