inside the playbook

A ‘portfolio’ of schools? How a nationwide effort to disrupt urban school districts is gaining traction

Several years ago, Indianapolis Public Schools looked like a lot of urban school districts. The vast majority of students attended traditional public schools, though enrollment was dwindling, and the district had an adversarial relationship with its small but growing number of charter schools.

That’s no longer true. The district is actively turning over schools to charter operators, and it’s rolling out a common enrollment system for district and charter schools that could make it easier for charters to grow. Nearly half of the district’s students now attend charters or district schools with charter-like freedoms.

It’s a remarkable shift that many in Indianapolis credit to — or blame on — the Mind Trust, a well-funded local nonprofit with a clear vision for improving education in Indianapolis.

Since its founding in 2006, the organization has called for dramatic changes to schools; recruited outside advocacy, teacher training, and charter groups; and spent millions to help launch new charter and district schools. The Mind Trust’s vision has also won support from the school board — which was elected with the financial backing of Stand for Children, an advocacy group recruited by the Mind Trust.

“They’re more influential than the IPS school board and the IPS superintendent,” said MaryAnn Schlegel Ruegger, an Indianapolis public schools advocate who has been critical of the Mind Trust’s role.

Now, a Mind Trust–style organization may be coming to a city near you.

A growing number of philanthropists, advocates, and policymakers say the way to improve schools is to upend the traditional school district. Usually pointing to the same cities as models — Indianapolis, along with Denver, New Orleans, and Washington D.C. — they want to see more charter schools and more district schools run like charter schools.

In their idealized vision, families are free to choose schools outside their neighborhood using an enrollment system encompassing all schools. The district gives up most of its traditional role setting policy for schools and instead becomes the body holding all kinds of schools accountable by closing ones that don’t succeed.

Together, those ideas make up what’s known as the “portfolio model” for managing schools, and its advocates are making a significant mark on a number of American school districts. Their sights are set on even more.

From Atlanta to Cincinnati to Oakland, a loosely connected network of nonprofit groups is working to reshape the way their school districts function. Their national scope has gone mostly unexamined, even as their influence is arguably far more likely to affect schools in the average American city than a Betsy DeVos-inspired voucher program.

Over time, something close to a playbook has emerged from their work. It’s not an exact sequence, and people within the same camp have different opinions about exactly what it should entail.

This is a look at how we got here, a few of the essential steps to reshaping a traditional school district, and what happens next.

A model emerges: Dozens of cities and millions in support

To understand the growing movement, a good place to start is with Ethan Gray and his organization, Education Cities.

The group started as a project of the Mind Trust, which hired Gray to create a network of peer groups across the country. Gray says his views were deeply influenced by the Mind Trust’s founder and leader David Harris, who helped him “understand how all the different pieces fit together when you’re trying to catalyze major change at the city level.”

Ethan Gray, head of Education Cities.

“Give us the freedom from overly prescriptive regulation and micromanagement, and in turn we will promise to help kids achieve on assessments at a certain level and create a strong school culture,” said Gray, who believes the traditional district model has fallen short, pointing to low test scores and vast achievement gaps.

Those ideas came originally from the academic world, specifically the University of Washington, where a professor named Paul Hill founded the Center on Reinventing Public Education in 1993. There, Hill pushed the idea that the key to improving schools was to rethink school boards.

Instead of operating all schools, boards should oversee them, focusing on which ones do best and worst, he argued. “Like investors with diversified portfolios of stocks and bonds, school boards would closely manage their community’s portfolio of educational service offerings, divesting less productive schools and adding more promising ones,” Hill wrote more than a decade ago.

The stock-market imagery was not a stroke of marketing genius when it came to winning allies in public education, and some advocates still bristle at the term “portfolio.”

“Diane Ravitch and the teachers unions now call us ‘corporate reformers’ and the phrase ‘portfolio model’ plays right into their hands,” said David Osborne, the author of a recent book that rebrands the approach as the “21st century schools” model.

Some charter critics accuse the portfolio model of being a plan to turn all schools into charters, as essentially happened in New Orleans, one of the models for the movement. Osborne argues that districts shouldn’t run schools, instead leaving that to outside groups. Gray insists it can work with district schools, and already is in Denver and Indianapolis.

But even as portfolio advocates differ on some specifics, they are united by broad beliefs, and brought together by unifying hubs. CRPE, the think tank now led by Robin Lake, regularly gathers districts interested in the portfolio model, and Education Cities, which has helped start some of the nonprofit groups, convenes them and offers advice and consulting.

Their work spans the country. Education Cities now counts 32 separate member organizations in 25 cities. So while Gray’s group itself is moderately sized, with around a $2 million budget and a dozen staff members, the ecosystem of independent local groups being built around its ideas is much larger in scope.

Education Cities member groups span the country

Click to enlarge. (Sam Park)

Member groups exist in three cities often promoted as models: in Indianapolis, it’s the Mind Trust. In New Orleans, it’s New Schools for New Orleans. Denver — a district with a self-described portfolio-management team — has two local philanthropies in the Education Cities network, and a new organization recently opened there that Gray says he helped advise.

Potentially representing the next wave of the movement, other member groups operate in cities like Kansas City, Philadelphia, and Oakland, which have not generally embraced the portfolio model.

Those organizations, which Gray calls “quarterbacks,” distribute money to get the portfolio approach off the ground in their cities — supporting schools seen as successful (often both charter and district schools), pushing for policies like common enrollment, and recruiting national education groups like Teach for America, Relay Graduate School of Education, TNTP, and Stand For Children.

Exactly how much money has flowed to support the portfolio model across the country is unclear. But prominent philanthropies, including some that have also spent millions in recent years funding charter schools nationwide, are investing heavily.

Education Cities is supported by a number of them, including the Dell and Walton foundations, as is CRPE. (Walton also supports Chalkbeat. Read more about our funding here.)

Many of the member groups are headed by former charter leaders and receive money from those national foundations, who see their investments as creating proof points that could become models for other cities. The Mind Trust, for instance, says it has raised $77 million since its inception in 2006, the bulk of which cames from local donors and a third from national groups.

The philanthropy that has most clearly embraced the portfolio model is the Arnold Foundation, whose K-12 education work is now led by Neerav Kingsland, the former head of New Schools for New Orleans. The Arnold Foundation has awarded a nearly $2 million grant to Education Cities and millions more to a handful of local quarterback groups, including the Mind Trust.

“If The Mind Trust can help to produce … gains in Indianapolis, the city can serve as a model for other communities across the nation,” John Arnold said in a video explaining his foundation’s investments.

But Education Cities operates on the principle that good ideas alone won’t reshape districts.

“We’re skeptical that systems themselves will actually go through some sort of self-driven transformation,” Gray says.

That’s where the nonprofit “quarterbacks” and their allies come in. They have varying perspectives and priorities, and there isn’t a set sequence of actions that they all take. But for simplicity’s sake, here are three common pieces of their strategy.

Strategy #1: Apply outside pressure.

Rather than waiting for districts to improve their schools, the groups pressure them to change course by directly supporting schools they see as effective and by creating new schools altogether.

The Mind Trust, for instance, partners with Indianapolis Public Schools to help select, fund, and launch new innovation schools. Those schools are run by outside operators, not unionized, and free from district rules around things like teacher pay or length of the school day, though they are officially counted as district schools.

The Philadelphia Schools Partnership, an Education Cities group, funded the opening of five new schools (four charters and one district-run) last school year. Great Public Schools Now, a Los Angeles-based group, pledged nearly $4 million to expand five district schools and has helped pay for a charter school’s new building.

In other cases, that means inviting charter operators to include the local market in their expansion plans, like when the Mind Trust tried to bring the Rocketship charter school network to Indianapolis, though ultimately no Rocketship schools opened there.

The idea is that with new, high-quality schools attracting local students, school districts may have to close their lowest-performing schools to stay solvent — a process some see as a feature, not a bug.

Myrna Castrejón, the head of Great Public Schools Now, at a town hall event. (GPSN)

“To the extent that our expansion creates the urgent need for [district] realignment and closures, I think we would be very supportive of that,” said Myrna Castrejón, the head of Great Public Schools Now.

“We believe strongly [that] schools shouldn’t have an automatic right to taxpayer resources in the absence of effectiveness,” said Mark Gleason, the head of the Philadelphia School Partnership.

Advocates for the idea of opening new schools and closing others based on performance often point to New Orleans, where the school district was dismantled after Hurricane Katrina in 2005 and has been almost completely replaced by charter schools. Charters there are largely free to operate as their leaders see fit, but their student performance is monitored, and a number have been closed for low test scores.

Test scores have improved dramatically across New Orleans in the years since, though some of those gains appear to have faded recently. Research found a substantial chunk of the improvements came from closing or replacing existing schools.

But the success of school closures or takeovers is far from guaranteed.

Students’ new schools are not necessarily better; for instance, the Achievement School District in Tennessee, which had charter operators take over district schools and has been praised as a leader in implementing the portfolio model, did not improve test scores.

Districts also don’t always close schools quickly, resulting in students and resources being spread thin across all schools. And when they do shutter schools, communities often resist, worrying about the loss of a local institution.

“I’m concerned about the number and burden of closures on particular communities,” said Terrenda White, a professor at the University of Colorado who has questioned the success of Denver’s school reforms. “That means more risk for displacement of kids and teachers.”

Strategy #2: Push for one-stop school enrollment.

Another piece of the portfolio playbook is supporting enrollment systems that allow families to easily choose among district and charter schools.

Adding new schools and new choices can make things harder on parents, who must navigate several enrollment processes to make a choice and get assigned to a school. Common enrollment systems create a single place to navigate it all — while also ensuring that all parents are exposed to new schools, and making it especially clear to district leaders which schools are attracting the fewest students.

“In addition to efficiency for families, unified enrollment helps the system make better decisions about which schools to replicate, recruit, incubate, scale, and maximize and, perhaps, where to locate them,” according to an Education Cities report.

Denver, New Orleans, and Washington D.C. all have common enrollment systems, and Indianapolis just adopted one. In Denver, the use of a streamlined system did in fact increase enrollment in charters among low-income students and English-language learners, though in New Orleans parents said it was actually harder to navigate initially.

"We believe strongly schools shouldn’t have an automatic right to taxpayer resources in the absence of effectiveness."Mark Gleason, Philadelphia School Partnership

In places where this system doesn’t exist, Education Cities groups are often pushing for it.

The Philadelphia Schools Partnership created a detailed plan to unify enrollment in the city’s district, charter and private schools, though the idea hasn’t taken off. Oakland-based Educate78 also spearheaded an ultimately unsuccessful effort to create a common system for district and charter schools with a $300,000 grant. The head of SchoolSmartKC, a Kansas City group, has testified before the state legislature in favor of a unified system, though the district’s superintendent says he’s skeptical.

While charter critics see the approach as a veiled effort to expand charters, centralized systems like this have also drawn another surprising adversary: more conservative supporters of school choice.

These free-market charter supporters fear that a single entity — a portfolio manager — with the power to manage enrollment and choose which schools to open and close would actually limit choice, put too much focus on test scores, and risk allowing unions to wrest control of the entire apparatus.

In fact, in 2016 it was Betsy DeVos, now the U.S. Secretary of Education, who was the key opponent of a plan to create a commission to act like a portfolio manager in Detroit, an effort spearheaded by an Education Cities member group in the city.

Strategy #3: Create a very different power structure.

Outside groups like the Education Cities quarterbacks can only do so much to implement this vision.

To see it brought to life requires the buy-in of the school board, mayor, or state — whoever runs the schools. That’s why the portfolio approach has gained particular traction in districts where states have taken over the schools, including New Orleans, Newark, and Lawrence, Massachusetts.

The groups and schools that the Indianapolis-based Mind Trust — whose logo is at the center — have supported. (The Mind Trust)

In other instances, supporters of charter schools have pushed change in school districts by working to fill local school boards with people sympathetic to the portfolio model.

Indianapolis is a case in point. The Mind Trust recruited Stand For Children, an advocacy organization that supports political candidates. In the 2012 election, Stand-endorsed candidates shifted control of the school board.

The organization doesn’t have to disclose how much it spent to support school board members in the city, but Stand for Children’s annual report says that in 2012, it “help[ed] elect two new members to the Indianapolis Public Schools board, which [led] to the exit of an ineffective superintendent.” The report also claims credit for school board victories in 2014 and 2016.

The capture of the school board cleared the way for many subsequent changes, including the hiring of a superintendent Lewis Ferebee who has supported a portfolio vision of the school district.

“If you look at Indianapolis, there’s no way to implement the vision without democratically controlled support,” Gray said.

School boards favorable to a portfolio-aligned vision have also been elected in Denver and more recently in Los Angeles, with financial backing from wealthy advocates of charter schools. Those charter school supporters have matched and sometimes exceeded spending by unions in a number of school board races previously dominated by teachers groups.

The portfolio model undercuts the unions and associations that represent teachers in other ways. The biggest is by reducing the number of schools whose teachers belong to the union, diminishing the union’s membership — and thus its power and its money.

The degree to which this is true depends on the political climate: in Indianapolis, innovation network schools are not under the district’s collective bargaining agreement, and thus lose certain job protections. Denver’s innovation schools can waive certain parts of the union contract, though teachers can still choose to join the union.

But most charter schools are not unionized. In New Orleans, soon after Hurricane Katrina teachers in the existing district were unilaterally fired, gutting the United Teachers of New Orleans, which has since organized at a handful of charters.

To some advocates, the reduction in union strength is integral to the model. They see an entrenched bureaucracy, maintained by “adult interests” — usually code for teachers unions — as the problem, and the portfolio vision as the solution.

“More than any other single reform this model breaks the political stranglehold interest groups have over elected school boards,” writes Osborne in his book “Reinventing America’s Schools.” (Osborne recently compared teachers unions’ opposition to charter school expansion in Massachusetts to George Wallace’s promotion of mandated school segregation.) Osborne’s work has been funded by prominent philanthropic supporters of charter schools and the portfolio model: the Arnold, Broad, and Walton foundations.

Some worry about the role of philanthropy, big-money donors, and state takeovers as undermining local, democratic control.

"We’re skeptical that systems themselves will actually go through some sort of self-driven transformation."Ethan Gray, Education Cities

“As elected school board members, once our term is up, we come back up for consideration,” said Jennifer Wolfsie, a school board member in Kansas City. “If the constituents I serve are not happy they have the opportunity … to vote me out,” she said. “In philanthropy, there isn’t that process.”

Huriya Jabbar, a professor at the University of Texas at Austin who has studied New Orleans schools post-Katrina, acknowledges the large test-score gains in the city as a result of the reforms. But, she said, that came with a cost: community buy-in, in the wake of the mass dismissal of New Orleans’ largely black teaching force and the state takeover of most of the city schools.

“Even advocates of the reforms have acknowledged that the one thing they got wrong was community,” Jabbar said. “And I think of that as quite a big thing.”

The future: The portfolio idea in the DeVos era

Exactly how far these groups will be able to push their school districts toward a new way of running its schools is unclear. Few places are like Indianapolis or Denver, with strong political support for the model — and New Orleans’ hurricane-induced changes make it entirely unique.

New quarterback-style groups have continued to emerge, including ones recently formed in Atlanta, Denver, Kansas City, and Memphis. But other Education Cities members have faced setbacks.

In Nashville, the group Project Renaissance recently scaled back its operations, and despite heavy involvement from Stand for Children, charter skeptics maintained control of the school board in elections last year. A Detroit group also recently closed down, though the Skillman Foundation there remains an Education Cities member.

One place where there is no Education Cities group: New York City, which under former Mayor Michael Bloomberg was held up as a model by portfolio advocates like Paul Hill. That approach was substantially altered by Bloomberg’s replacement, Bill de Blasio, who has been cool to charters, slowed school closures, and reduced principals’ autonomy.

These setbacks underscore the challenges portfolio advocates will face in advancing their vision. Even its supporters disagree on a number of points — how clear their case is for a nationwide expansion, what strategies to pursue, and whether the model can work for district-run schools.

Meanwhile, the effort comes in a perilous time for charter school supporters, as nationwide support has dropped and they have become linked to an unpopular president and education secretary.

But for left-of-center charter backers, the portfolio approach presents an opportunity to position their brand of school choice as distinct from DeVos and other conservatives, who emphasize private school vouchers and want few limits on parent choice.

“Our model is probably different from the model of the [Trump] administration, and it’s not the same model of, if you would, a traditional school district,” said Henderson Lewis Jr., the head of the district that oversees New Orleans charters, in a recent interview. “We’re somewhere in the middle, which I see as a third way.”

This is part one of a three-part series. Part two takes a closer look at how the portfolio movement has played out in one city; the third part examines what research says about this emerging strategy.

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the portfolio push

With big names and $200 million, a new group is forming to push for the ‘portfolio model’

An advisory period in a classroom at Washington Latin Public Charter School, in Northwest Washington, D.C. (Photo by Allison Shelley/For The Washington Post via Getty Images)

Several big names in education reform are teaming up to start a new organization designed to change how schools are managed in cities across the U.S. — and they say they’ve already raised $200 million.

The City Fund, as the group is being called, will push cities to expand charter schools and district schools with charter-like autonomy. It represents a big increase in visibility and influence for advocates of the “portfolio model” of running schools, a strategy that’s been adopted by cities like New Orleans, Denver, and Indianapolis.

The group was announced Tuesday morning on the blog of Neerav Kingsland, who leads education giving at The Laura and John Arnold Foundation. According to a separate presentation created by the group and viewed by Chalkbeat, the Arnold Foundation and the Hastings Fund have already given the group over $200 million. It’s unclear if the organization has raised additional funds.

Although the group is likely to start in a small number of cities, that presentation also made its ambitions clear: it aspires to eventually be in “every city in America.”

Others involved include Chris Barbic of the Arnold Foundation; Kevin Huffman, the former Tennessee education chief; David Harris, who previously led the Mind Trust, an Indianapolis-based group; and Ethan Gray, the president of the nonprofit Education Cities.

“We believe that school systems can succeed when schools operate with autonomy while being held accountable for strong student results,” the group said in a job posting, which has since been taken down.

The group will be advocating for a brand of school reform that has gained traction in a number of cities, but remains controversial.

The basic idea is that families should be able to choose among different schools, and that those schools should be free to operate as they see fit. In addition, schools should be held accountable for their performance — largely based on test scores — with good ones growing and bad ones closing, while an oversight body coordinates essential functions like enrollment across schools.

Cities that have adopted much or all of this portfolio approach include Denver, Indianapolis, and New Orleans, as well as Camden and Newark, New Jersey. In each of those cities, charter schools have expanded rapidly. Some of those cities also have a hybrid, where district schools are granted charter-like autonomy or charter operators take over district schools.

“Cities across the country are constantly innovating, and when a few cities do something that seems to be working, philanthropy can help shine a light on these local successes,” the group’s blog post says.

The City Fund’s founders have experience with those cities. Kingsland ran New Schools for New Orleans, a group that coordinated education advocacy and philanthropy in that city after Hurricane Katrina. As Tennessee commissioner, Huffman helped create the state’s Achievement School District, which Barbic ran and which turned district schools over to charters. Harris led the Mind Trust, an Indianapolis group that influenced the education strategy of the city’s central district. Gray’s Education Cities has spent the last several years convening local nonprofits pushing these ideas in two dozen cities.

But Education Cities’ budget was around $3 million in 2016. The City Fund’s aspirations — and budget — appear to be much bigger.

If the $200 million figure is designed to last for several years, the City Fund would remain significantly smaller than the biggest players in education philanthropy, though large enough to make an impact. The Walton Foundation spent about $191 million on U.S. education in just 2016, for example, and the Bill and Melinda Gates Foundation spent about $367 million.

The group has indicated that it plans to influence local organizations by providing funding, obtaining seats on their boards of directors, offering strategic advice, and convening groups from different cities, according to people familiar with their plans.

These local “quarterback” organizations, as they’re sometimes called, are designed to be the nonprofit hub of a city’s portfolio strategy — doling out grants to grow schools seen as successful, seeding groups that influence school board elections, creating and advocating for new policies like unified enrollment systems.

Its approach is sure to face fierce pushback — and already has in many cities.

Skeptics of charter schools will surely oppose this effort to expand charters and other schools not governed by a school board; they’ll also likely see it as an attempt to weaken teachers unions. Indeed, some advocates for the model say that a key goal is to limit the power of teachers groups by growing schools where teachers aren’t unionized.

Across the country, charter school expansion has drawn pushback as districts lose students and money, in some cases pushing schools to close. Nationally, polls indicate that support for charters has fallen, particularly among Democrats.

On the other side, free-market advocates see the portfolio model as actually limiting school choice, putting too much power in the hands of the “portfolio manager” and shutting down schools based on their test scores, rather than parent demand. In 2015, before she was Secretary of Education, Betsy DeVos successfully led the opposition to an effort to create what amounted to a portfolio model in Detroit on those grounds.

Another major risk for the group is operating from a national perch with national funding.

This has tripped up advocates of the portfolio model before. In 2013, for instance, Gray of Education Cities released a plan to have Kansas City adopt the portfolio model if it were taken over by the state. The idea set off a firestorm and was never implemented, not least of all because it was being pushed by a national group with few ties to the city.

Advocates for the approach argue that it will help students in cities that have long struggled with academic performance, though the evidence of its effectiveness is limited and mixed.

Their argument has gotten both good news and bad news in recent weeks. While a new study showed substantial increases in high school graduation, college enrollment, and college completion rates in the wake of school reforms in New Orleans, another found that the Tennessee turnaround district that Barbic led produced no gains in test scores even after five years.

“We’ll also work with university researchers to study these local efforts,” the blog post said. “If cities show progress, we hope other cities will follow. If they don’t, we hope other promising innovations are able to scale, so that all students can have access to amazing public schools.”

Education Cities itself is shifting focus, according to a message on its website Tuesday morning, as Gray and some staff members move to The City Fund. Education Cities will be supporting two new organizations, one aimed at advising school board members and the other aimed at helping education groups partner with communities.

research shows

Advocates of the portfolio model for improving schools say it works. Are they right?

PHOTO: Caroline Bauman

Author David Osborne is sure that his vision for improving schools is the right one: “If you discovered a cure for cancer, but it was politically difficult with your union, would you avoid it?”

Neerav Kingsland, another proponent of the idea known as the “portfolio” model, is also optimistic but more cautious. “There’s enough evidence to try it in eight to 10 cities and see if we get good results,” said Kingsland, who leads one foundation’s efforts to parcel out funding for the approach.

“This reform effort might work and so I think it’s really worth trying,” Kingsland said. “We just need to be sober with the evidence.”

As with many education policies, the portfolio model is gaining adherents even while an research base is still being built. Those philanthropists, nonprofit groups, and policymakers — like Kingsland at the Arnold Foundation and Osborne, on a multi-city book tour promoting the approach — are betting big on the idea that schools should be managed more like stocks in a portfolio, where successful ones should expand and failing ones should close.

They point to schools in New Orleans, Denver, Indianapolis, and Washington, D.C., cities that have embraced the model to varying degrees and have seen some education metrics tick up over the last several years.

Whether that amounts to an open-and-shut case for the model is less clear. Here’s a guide to what we do know, and how you can weigh the claims.

First, you should know: It’s difficult to study the portfolio approach, because it’s not a single idea.

Instead, it’s a package of policies that get grouped together, usually put in place across a whole district or city. That’s why comparing districts that have tried the portfolio approach to ones that haven’t is arguably the best approach for finding out whether it “worked.”

But school districts are complicated. Totally different policy changes, or shifting demographics like an influx of wealthier or poorer students, can affect districts too. Without controlling for all of that, a school district’s improvement doesn’t tell us much. That’s where rigorous research comes in.

But there is little or no rigorous research comparing gains in Denver, Indianapolis, and Washington D.C. to similar districts that have gone in a different direction. That doesn’t mean it hasn’t worked in those places — it’s just hard to know.

Second, the gains in New Orleans make a case for the portfolio model.

The city that has most clearly embraced the portfolio approach, New Orleans, has seen big academic achievement gains relative to other districts in the state.

PHOTO: Tulane University's Education Research Alliance
Student achievement in New Orleans increased relative to similar school districts.

These results were not because of changes in the types of students in the city, according to a Tulane study, and the effects were quite large — akin to seeing the average student in New Orleans gain 8 to 15 percentile points on state tests relative to other Louisiana students between 2007 and 2012. The package of policies also coincided a sharp increase in high school graduation and college attendance.

A national analysis also found that New Orleans students made large academic gains between 2009 and 2015. However, more recent test scores in the city have suggested that schools are backsliding somewhat.

But even those results don’t prove New Orleans’ academic success came from the portfolio model.

A significant share of the city’s academic gains seems to have come from closing low-performing schools. Less talked about — and generally not discussed as part of the portfolio approach — is the substantial infusion of money for schools. This was not just a one-time grant of cash to help schools rebuild: Even several years after Hurricane Katrina, New Orleans schools were spending nearly $1,500 more per student than districts that previously spent the same amount on their schools.

“In most of the places that are thinking about this [model], they’re not thinking, OK, let’s increase spending 15 percent the way they did in New Orleans,” said Doug Harris, the researcher who conducted the Tulane study.

That raises another question about the portfolio model: Even if it succeeded in New Orleans — a very specific context — is it likely to succeed elsewhere?

There’s helpful research on a few other cities. It comes to a mix of conclusions.

In Lawrence, Massachusetts, one study found that the state’s takeover of the district led to substantial gains in math, modest improvements in English, and a growing share of students progressing through high school on schedule. The gains seem to have been driven in large part by expanded learning time, particularly small group tutoring over vacation breaks for certain students.

Lawrence’s approach included aspects of the portfolio model — including a focus on autonomy and accountability — but not others, like school choice.

In Newark, controversial reforms spurred by a $100 million gift from Mark Zuckerberg seem to have had mixed success. Five years later, schools in Newark have higher growth rates in English, but not in math, according to a recent Harvard study, which also found a decline in performance in both subjects in the first three years of change.

The changes in Newark included closing down low-scoring district schools, expanding higher-performing charters, and creating a common enrollment system. Efforts to shift students to better schools seem to have been successful, but existing schools often got worse.

Perhaps the most disappointing results for the portfolio approach come from Memphis. A Vanderbilt analysis found that a state takeover effort known as the Achievement School District failed to raise test scores, even as it was dubbed a “national exemplar” in implementing the portfolio model. Another approach known as the iZone, which granted other Tennessee schools more autonomy, did lead to improvements, according to the same study.

Most of these studies can’t definitively show which specific changes were more or less successful, though.

Studying the portfolio model as a whole is hard. So let’s separate the parts: We do know a lot about charter schools and where they work best (at raising test scores).

Research on charter schools is especially relevant, since the portfolio approach essentially aims to treat every school like a charter — and often leads to a growing charter sector.

A number of national studies show that their charter school students perform about the same as those in nearby district schools. Evidence on charter schools’ long-run impact is still thin.

But research focusing specifically on charters in cities and their impact on disadvantaged students paint a brighter picture. Most studies do show that, in that context, charters — particularly those in nonprofit, city-based networks — are more likely to boost test scores. That’s also been shown in Boston, Chicago, Denver, Indianapolis, Los Angeles, Newark, New Orleans, and New York City.

Supporters of the portfolio model can point to these successes to support their approach, which is focused on cities. There are questions, though, about whether those charter schools perform well in part for reasons other than better teaching, like attracting more girls than boys, not filling empty seats in later grades, or getting substantial amounts of outside money.

School closures can help if students have better options.

The portfolio model emphasizes holding schools accountable for performance — which may mean closing them.

The research on closures has found that in some cases it helps students, in others it hurts them, and sometimes it doesn’t make a difference. Recently, a large national study found that closing low-achieving schools had no overall effect on the displaced students’ test scores.

However, there is strong evidence that, as happened in New Orleans, when students leave closed schools for ones with better test scores, their scores improve, too — and that is closely in line with the theory of portfolio advocates.

Whether school autonomy, another aspect of the portfolio model, really boosts learning is unclear.

On its own, giving district schools more authority over operations like staffing and curriculum has not been shown to consistently improve student learning. For instance, modest efforts along these lines in Boston and Denver haven’t boosted test scores. But results are more positive for Indianapolis’s “innovation schools” and Tennesse’s iZone, both instances where schools were granted additional freedom.

As for negative side effects like increasing segregation, there’s not a lot of research to go on.

Critics of the portfolio model say there will be negative consequences of the model, beyond any changes in test scores. Some of these — like the potential reduction in democratic control caused from letting outside operators runs schools — aren’t about data or research.

Does the portfolio model increase school segregation? Charter schools, which have often expanded in portfolio districts, have been shown in some cases to exacerbate segregation. In districts that have adopted the portfolio approach, the pattern isn’t clear: In New Orleans, the expansion of charters and the portfolio approach had little net effect on segregation, but charter schools in Indianapolis do seem to exacerbate segregation. In Denver the share of students who attend economically segregated schools has dropped moderately since 2012.

Does the portfolio model mean sweeping out veteran teachers of color and replacing them with white teachers? New Orleans has seen a significant decline in the share of black teachers — from about 70 percent to nearly 50 percent — in the wake of the changes, though the loss of black teachers has been seen in a number of other cities as well (including some that didn’t implement portfolio-style changes).

Are there other negative side effects? Some New Orleans principals have acknowledged pushing out low-performing students. (Policymakers have made efforts to address that, though there hasn’t been follow-up research to examine whether those changes have been successful.)

Another concern: expansion of charters in New Orleans coincided with a decline in the number of schools offering prekindergarten, which has been shown to benefit students in the long run.

One potential downside that doesn’t seem to have come to pass in New Orleans: an increase in students moving between schools, which can be disruptive. If anything, the opposite happened, and students changed schools less often.

This is the final part of a three-part series. Part one looks at the push to expand the portfolio model in cities across the country; part two examines how the portfolio movement has played out in one city.

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