A charismatic charter network leader reminded us recently of his high-poverty schools’ laudable learning results. His secret sauce? Wooing the best teachers and principals away from surrounding districts.

We call this a “Talent Hog” strategy, and its prevalence explains, in part, why reforms that succeed in some schools fail at scale—leaving cities, states, and their children, back where they started. There is a better way, but it requires a policy solution.

For the record, this leader isn’t alone; many districts boast of the same strategy. Sometimes, we’ve even helped them plan and execute it. After all, teacher and principal quality are the top two factors within schools’ control that affect learning outcomes. New reforms—curricula, teaching methods, professional development, technology, governance, and so on—succeed or fail based on how well educators actually use them.

What’s wrong with Talent Hogging? What’s good for each enterprise—districts, charter school networks, and individual schools—neutralizes education reform in their communities, settling average learning growth near where it would be without reforms.

When a school recruits a great teacher—one who more often produces high-growth learning for more kids—from another school, the students in the recruiting “Hog” school benefit. But an equal number of students, on average, in the losing “Hungry” school miss out.

Naturally, every leader wants to be a Talent Hog, not talent hungry. Some excel at recruiting. Like our charter friend, they may have charismatic leaders or offer appealing working conditions. Learning results may follow for them, but the Hogs are depriving students at somebody else’s table.

Systems can recruit more broadly, attracting applicants from across their state, a neighboring state or the nation. But whatever you consider your “community,” when the primary talent strategy is talent hogging, one set of students benefits at another’s expense.

What is the solution? It isn’t discouraging school systems from working hard to attract and please great teachers and principals. It’s good for educators if employers are hustling to get and keep them.

Instead, the solution is changing—at large scale—how great teachers and principals are deployed.

That requires policy incentives for school systems to extend the reach of excellent educators, ones already on staff and ones they recruit. Those educators—the ones who help students make significantly higher growth—need better-paid career options that help all educators excel.

Instead of hiring teachers into one-teacher-one-classroom school models, systems must be encouraged and supported to redesign roles, budgets, and schedules to put their limited number of excellent teachers in charge of small teaching teams, for more pay, within regular budgets. Similarly, great principals should be able to lead small clusters of schools.

By leading small teams through intensive guidance and development, each excellent educator can positively impact the student outcomes of five or six educators. At scale, that has the potential to reach literally all students with excellent instruction. With help like this, far more teachers excel. Well-led teams can help systems “grow their own,” creating internal pipelines to supply these multi-classroom leaders and principals for the future.

Our Opportunity Culture initiative, now entering its eighth year, shows one way to do this, with strong results. Third-party researchers found that when team teachers, who started out producing growth at the 50th percentile on average, joined small teams led by proven excellent teachers called “multi-classroom leaders,” they produced growth in the 75th to 85th percentile in math, and the 66th to 72nd percentile in reading (in six of seven statistical models).

Why not just add more great teachers to the system? Yes, Teach For America and lateral-entry programs draw people into teaching. But they are a drop in the bucket: Teach For America provides about 3,000 to to 5,000 new teachers annually, while about 260,000 new entrants are needed nationally.

Here’s the bottom line: You can’t scale up excellence across a whole city, state or nation if every enterprise is motivated merely to be a Talent Hog. Policymakers and leaders have to disrupt enterprise leaders’ natural instincts through policy, by incentivizing leaders to introduce well-designed multi-classroom and multi-school leadership.

Districts and charters will still have to compete for talent: Data indicate, in fact, that having an Opportunity Culture district within commuting distance of another jacks up student learning growth in both locations. But no school need go hungry—all can have the talented educators they need to reach all students with classroom excellence.

Until this happens, charters and choice and districts and their host of school improvement efforts will all be doomed. Hungries will outnumber Hogs, and most students won’t achieve the learning they need to catch up and leap ahead.

Emily Ayscue Hassel and Bryan C. Hassel are the co-presidents of Public Impact.