In the United States, there is famously little consensus on the topic of climate change. But among the community most concerned about it, certain convictions are widely shared: Fossil fuel emissions deserve nearly all the blame for warming our planet. Meat—especially from flatulent cattle—is an environmental scourge. The Koch brothers, with their campaigns against solar power and cap-and-trade legislation, are (to avoid a less printable word) jerks. And we are probably all doomed.

But over the past few years, a new strain of environmental thinking has begun to challenge nearly all of these tenets. This growing movement includes climate activists, scientists, and also farmers, who play a key role. Many of them would agree with mainstream environmentalists about the Koch brothers. But they argue that the way we’ve been thinking about climate has been, if not all wrong, at least woefully incomplete.

The core premise of their thinking is a belief in the overlooked importance of soil. Carbon, harmful at current levels in our air and water, is essential in the ground, where it makes soil rich and fertile. Our greenhouse-gas problem, they argue, began long before we realize, with agricultural mismanagement and other disruptions of land deep in human history, and solving it depends on restoring our soil to the point where it pulls immense amounts of carbon out of the atmosphere—possibly enough to reverse the effects of industrial emissions.

Throughout the country and abroad, farmers and rangers have begun experimenting with innovative ways of planting crops and grazing animals that are intended to revitalize the soil. The best known is a particular method of raising livestock devised by biologist Allan Savory, born in what is now Zimbabwe, who offers a vision of land management that would send cows grazing across the American plains, emulating the ancient herds of ruminants that once trampled and enriched grasslands.

The movement has spawned a number of advocacy organizations, including the Soil Carbon Coalition, an Oregon-based group whose motto is “Put the carbon back where it belongs.” Scientists have been studying the carbon storage capacity of soil to determine what is possible. And enthusiastically chronicling all of these developments is a small cottage industry of recent and forthcoming books: “The Soil Will Save Us,” by Kristin Ohlson; “Cows Save the Planet,” by Judith Schwartz; “Grass, Soil, Hope,” by Courtney White. All of them are characterized by an upbeat optimism at odds with the often bleak outlook of the traditional green movement.

“When we’re only talking about reducing fossil fuels, it’s depressing because as individuals we feel helpless,” said Schwartz. “When you start to look at the function of the soil and land, things look very different.”

This optimism can be tremendously seductive, and takes the form of some lavish claims—Savory has said that if his method were widely implemented, we could suck enough carbon out of the air to return atmospheric carbon dioxide to preindustrial levels within a matter of decades. When you see things from the perspective of this movement, the problem seems paradoxically both much bigger than we realized, and much easier to solve.

Though they share goals, and offer largely complementary solutions, these new activists don’t always sit easily alongside the more conventional climate movement. Some complain that the latter focuses too single-mindedly on emissions while paying no more than lip service to other remedies. And they’ve engendered critics who believe that soil doesn’t have close to the carbon-storing capacity that Savory and some advocates claim—and that if the movement gains steam, it could shift the focus dangerously away from the imperative to cut fossil fuel emissions.

Still, even these critics agree that carbon sequestration in soil should be part of the answer. How big a part remains to be seen, but the conversation about climate has begun to change—and the tensions that emerge offer a window into the full scope of how human activity affects the planet, for ill and, potentially, for good.

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We may call it dirt, but soil is an enormously complex substance. When healthy, it’s moist, loamy, and black, teeming with living organisms. “The best way to describe it is just envision black cottage cheese,” says Gabe Brown, a North Dakota farmer who has gained renown in agricultural circles for his success in integrating crops and livestock. Much soil, though, bears more of a resemblance to a gray block of parmesan cheese. And the key ingredient that makes the difference—that allows all of that life to thrive—is carbon.

“If you scoop up some earth, you can see if it’s got carbon in it because it’s dark and it’s rich and it’s light, and it’s got many feet of fungal roots and roots of the plants holding it together,” said Adam Sacks, cofounder of Biodiversity for a Livable Climate, a Boston-area-based group that advocates for soil-based carbon storage. “It’s the most complicated ecosystem on earth. We know very little about how it works, but we know how it works when we use it, and when we abuse it.”

And for about 10,000 years, since humanity began practicing agriculture, we’ve been abusing it. Deforestation and plowing disrupt all of those exquisite networks, impoverishing the soil and releasing carbon into the air in the form of carbon dioxide. As far back as the 1950s, scientists were aware that loss of carbon from modern soil was possibly related to climate change.

According to one theory, there’s an additional contributor to the rich historical soil we are losing: animals. In the 1950s and 1960s, Allan Savory was a game ranger in his native Africa, where grasslands were rapidly turning to desert. His job involved closely observing the land and patterns of animal interactions with it, and he noticed that, contrary to conventional game ranger wisdom, clearing land of animals, to allow it to “rest,” did not help it recover; in fact, the land appeared to suffer.

The theory Savory developed, drawing on both agronomical thinkers and folk wisdom, held that wild herds of ruminants—bison, wildebeest, and so forth—displayed a cluster of behaviors that was essential to the health of the land. The animals bunched tightly in herds as a defense against predators. For a few hours or days they would graze on grasses and other plants, which stimulated plant growth; trample the ground underfoot, which left plant residue as cover; and deposit their dung and urine, which acted as fertilizer. Then they would all flee together to a different site, allowing the soil to absorb all those nutrients and the land to recover from the impact, and the process would repeat.

Humans have interrupted that process in various ways—by hunting the animals to extinction, by destroying their habitat, and by raising livestock with a completely different relationship to the land. Savory’s hypothesis was that rangers and farmers could reproduce it by managing livestock to mimic those ancient patterns. Working with pastoralists around the world, he began to implement this approach, which he calls Holistic Planned Grazing. (In a much-viewed TED talk last year, he brandished impressive before-and-after photos of land transformed from barren desert to lush and fertile terrain through these methods.)

His initial theory focused on improving the land, but eventually Savory came to see the soil as a powerful tool for capturing atmospheric carbon, and began to promote his idea as something much bigger: a way to fight climate change. In an e-mail interview, Savory lamented that biodiversity, desertification, and climate change are treated as separate problems. “But they are all one and the same issue—massive environmental disruption caused mainly by agriculture (the production of food and fibre from the world’s land and waters) and by fossil fuel use.” Holistic Planned Grazing, he believes, can help address all of them. (As for methane emissions from cattle, Savory and his supporters argue that they would be much more than offset by the carbon sequestration.)

Carbon sequestration isn’t a new idea—“carbon sinks” have long been considered one way to offset greenhouse gas emissions, whether in the form of new forests or exotic schemes to bury carbon in the ocean. But it has typically been seen as a sort of extra: By all means, plant some trees, but the most salient objective has been to stop burning fossil fuel and transition to clean energy. Savory, while agreeing with the need for that shift, switched the emphasis to capturing carbon—and saw far more promise in it than climate activists had.

Not everyone in the movement buys into Savory’s grazing theories; others focus more on planting patterns and cover crops. But like Savory, the advocates who have latched onto this idea see it as a corrective to the emissions-centric focus of the mainstream environmental movement, which they consider both too narrow and, so far, futile. “I see little hope of emissions reductions,” said Sacks of Biodiversity for a Livable Climate. “They’ve been a complete failure to date.” Seth Itzkan, president of the Somerville-based ecological consultancy Planet-TECH Associates, says: “I don’t want to berate the climate movement, but they also need to be doing something else. And the largest quickest way is ecological restoration and restoration of soils.”

The Savory Institute, founded in 2009, has established 10 Savory Hubs in various countries where people learn, teach, and locally adapt Holistic Planned Grazing. The past few years have seen a flourishing of related activity as well. Peter Donovan of the Soil Carbon Coalition has been traveling on an old school bus around the country trying to measure the carbon content of soil. Dozens of conferences and workshops have been held on the topic of improving soil health; the UN has designated next year the International Year of Soils. USDA scientists are working to understand better how soil works and how we can measure the carbon content.

“I do think that awareness of this dynamic is growing,” said Judith Schwartz, author of the 2013 book “Cows Save the Planet.” “There’s been incredible receptiveness.”

The movement has created some unexpected allies, attracting farmers and ranchers who are not typical environmentalists—indeed, who may not even believe in global warming. Healthy soil both absorbs much more water, meaning less runoff and flooding, and withstands drought better because of the water it retains. Even if soil played no role in sequestering carbon and mitigating climate change, it would help individuals to survive the extreme weather events that are projected to become more common. Soil quality also correlates with nutritional quality in crops and meat.

Gabe Brown, the North Dakota farmer, has implemented Holistic Planned Grazing as well as other techniques, such as cover crops, on his land. He has seen his soil go from dry and gray to black and crumbly, and says scientists who measured the carbon content in his soil found that in places it had tripled in the past 20 years. He says he speaks to other farmers at about 30 conferences and workshops each year. “They’re concerned about organic matter, but they do not think about it in terms of carbon sequestration and what it’s doing for climate change,” he said. “I’m going to catch a lot of flak for saying this: Carbon drives the system. It’s all about carbon.”

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For all the optimism of the soil-as-savior movement, and all the promise of isolated local experiments such as Brown’s, it’s far from certain that global soils have anywhere near the carbon-storage capacity we’d need to compensate for emissions.

Rattan Lal, a soil scientist and director of Ohio State University’s Carbon Management and Sequestration Center, says that, based on extrapolation of his measurements, the earth’s soil could theoretically absorb about three gigatons of carbon per year. Currently, he says, the atmosphere retains about 4.3 gigatons of emissions during the same period. “The problem is that this three gigatons is the maximum potential,” he said. “And then it cannot go on forever.”

According to Lal, in about 50 years, the soil would be saturated. In effect, he sees this approach as a way to buy us some time to shift to alternative energy sources. (Lal believes Savory’s method is an effective way to increase the soil’s carbon content, but focuses on other methods himself, such as mulch farming, conservation tillage, agroforestry, diverse cropping systems, and cover crops.)

There is also debate about the effectiveness of Savory’s specific approach. David Briske, professor of ecosystem science and management at Texas A&M University, agrees that fighting global warming by capturing carbon in soil “is clearly a valid concept,” but calls Savory’s more ambitious claims “highly misleading,” and believes Savory is “using carbon sequestration as a way to garner support for his grazing method.”

Others cite other numbers that suggest the soil has a higher maximum capacity, and believe that we can continue adding carbon to the soil, and even build new soil, far more than science has recognized. Assessing carbon content at the global scale is tricky because, among other reasons, there are different kinds of carbon, organic and inorganic. Kristine Nichols, a USDA scientist who studies soil, says that over time, organic carbon, which is more prone to cycling in and out of the air, can be stored, with proper management, for longer persiods of time—and over the very long term, some of this will form new fossil fuels. “There’s a tremendous amount of potential for the soil to absorb carbon,” said Nichols. “The potential in that soil environment is greater than the amount of CO2 that’s in the atmosphere…there’s more carbon that can be in that soil environment than we ever thought possible.”

In part, the argument about soil has turned into a tug-of-war about data, which on a subject this large and complex is often inconclusive or missing. “There are things we know we’re doing, but the data is not there,” acknowledged Daniela Ibarra-Howell, CEO and cofounder of the Savory Institute, which has begun to systematically gather information about the carbon content at the Savory Hubs.

Beyond data, there are questions of competing priorities. The climate movement has limited resources, and it has its hands full with emissions control: reducing what we pump into the atmosphere, finding long-term solutions that don’t use fossil fuels, and persuading governments to invest more money in regulating and developing these technologies. In this framework, even a well-intentioned movement that offers a shiny but uncertain promise is potentially a risky distraction.

“I think it might detract from the major issues of reducing fossil fuel emissions,” said Pushker Kharecha, a research scientist at Columbia’s Earth Institute, referring to Savory’s approach. “A heavy over-emphasis on land use as a panacea does detract from the more fundamental issue of shifting our energy infrastructure to clean energy.”

It’s not hard to see the appeal of a movement that promises not only a carbon sponge, but more delicious food, hardier land, and profits for small farmers along the way. Better soil also enhances food security for developing countries. That doesn’t make soil improvement the miracle cure its staunchest advocates claim. But given the magnitude of the challenge, there’s sense in the message that we can make the most of the resources we already have underfoot—even if, as we might have guessed in the first place, the world will not be saved by cows alone.

ON a recent Sunday afternoon, a monthly meeting convened around a long table in a Whole Foods cafeteria on the Upper West Side of Manhattan. As people settled in, the organizer plopped down a bag of potato chips and tackled housekeeping matters, like soliciting contributions. But she did not insist. “I know that some of you are in fragile situations,” she said.

One attendee recalled scraping by on $9,000 a year. “I was exhausted by years of living in poverty,” she said. Her neighbor chimed in: “Amen, sister.”

An eavesdropper might have been surprised to learn what the group had in common: formidable academic credentials. Sitting at the table were a historian, a sociologist, a linguist and a dozen other scholars. Most held doctorates; a few were either close to completion or had left before finishing. All had toiled for years in graduate school but, by choice or circumstance, almost none had arrived at the promised destination of tenure-track professorships (the one who had was thinking of leaving). Now they found themselves at a gathering of a group called Versatile Ph.D. to support their pursuit of nontraditional careers.

After a round of introductions, the participants broke into clusters to swap stories and tips. A 32-year-old man who had studied ancient religion at Princeton wore a T-shirt emblazoned with the name of his employer, a finance website; he talked up his job to a physicist who was finalizing her thesis. The historian, a teacher at an elite private school, advised a recent American studies Ph.D. on where to find job postings and how to package himself. That young Ph.D., Adam Capitanio, who completed his degree in 2012, had looked for an academic position for three years, focusing his search on the Northeast and applying for at least 60 jobs. He hadn’t received a single interview. Now he was working as an editorial associate at an academic publisher, trying to devise a long-term plan. “Things were kind of desperate before I had that job,” he said. “This gives me some flexibility to figure out what I actually want to do.”

Dr. Capitanio’s experience is far from unusual. According to a 2011 National Science Foundation survey, 35 percent of doctorate recipients — and 43 percent of those in the humanities — had no commitment for employment at the time of completion. Fewer than half of Ph.D.’s are expected to land tenure-track jobs. And many voluntarily choose another path because they want higher pay or more direct engagement with the world than monographs and tenure committees seem to allow.

Though graduates have faced similar conditions for decades, the past few years have seen a surge in efforts to connect Ph.D.’s with gratifying employment outside academia and even to rethink the purpose of doctoral education. “The issue itself is not a new issue,” said Debra Stewart, president of the Council of Graduate Schools. “The response, I would say, is definitely new.”

In addition to New York, Versatile Ph.D. groups have formed in at least seven other cities, including Philadelphia, Chicago and Los Angeles. Abundant online resources help Ph.D.’s turn curricula vitae into résumés and market their skills to nonacademic employers. And former academics can find kindred souls at blogs like “Chronicles of a Recovering Academic” and “Dr. Outta Here” (obscenity alert).

The spirit of change has even begun to take root inside the ivory tower. The University of California, Berkeley, held a “Beyond Academia” conference last spring, hosting Ph.D. speakers who have succeeded in other domains, from consulting to biotech. Similar events are planned at the Graduate Center of the City University of New York, which established its new Office of Career Planning and Professional Development in February.

The problem is especially urgent in the humanities. For Ph.D.’s in STEM disciplines (science, technology, engineering, mathematics), industry has long been a viable option. But students who study, say, Russian literature or medieval history have few obvious alternative careers in their fields. They confront questions about their relevance even inside the academy, let alone outside it.

In August, the Scholarly Communication Institute released a report titled “Humanities Unbound: Supporting Careers and Scholarship Beyond the Tenure Track.” In it, Katina Rogers, the lead researcher, discusses the nascent concept of alternative academic, or alt-ac, professions. The term has gained widespread currency (and its own Twitter hashtag) and can refer to jobs within universities but outside the professoriate, like administrator or librarian, as well as nonacademic roles like government-employed historian and museum curator.

Dr. Rogers suggests that alt-ac is less a matter of where you work than how — “with the same intellectual curiosity that fueled the desire to go to graduate school in the first place, and applying the same kinds of skills, such as close reading, historical inquiry or written argumentation, to the tasks at hand.” In an interview, she credited the neologism with infusing “positive energy” into the often gloomy conversations about alternative careers. The alt-ac ethos holds that nonacademic work is not a fallback plan for failures but a win-win: Ph.D.’s can bring their deep expertise and advanced skills to a whole gamut of challenges, rather than remaining cocooned in the ivory tower.

Karen Shanton explored unconscious cognitive processes for her philosophy Ph.D. from Rutgers but works at the National Conference of State Legislatures, which provides legislators with nonpartisan analysis. She won the two-year fellowship from the American Council of Learned Societies. Its Public Fellows program, created in 2011, places Ph.D.’s from the humanities and social sciences in nonprofit and government organizations.

Dr. Shanton said her education “absolutely” informs her work, which focuses in part on voter ID laws, as she draws on her writing and thinking skills as well as her knowledge of how the mind works. “It’s actually kind of great because it has a lot of the benefits of academia,” she said. But “with politics, you can have a sort of more immediate impact.”

While the alt-ac perspective is relatively rosy, some disenchanted academic refugees embrace what they call the “post-ac” identity. The website “How to Leave Academia” recently published a post-ac manifesto, defining the orientation as “a belief that the current system is flawed, cruel, unsustainable and therefore impossible to directly engage with.” In this view, Ph.D. programs, with their false promises, lure students to serve as cheap labor, first as teaching assistants, then as poorly paid adjuncts when tenure-track jobs elude them.

“Post-ac discourages people from pursuing graduate work,” write the authors, Lauren Whitehead and Kathleen Miller, under the pseudonyms Lauren Nervosa and Currer Bell. Dr. Miller also penned the blog post “I Hate My Post-Ac Job: What Happens When You Don’t Land the Perfect Postacademic Career.” In it she writes: “Graduating, leaving academia, moving to a new city, starting a new job, and then hating it? Sheesh. Let me tell you — it’s hard to feel like a success story.” Unable to secure academic employment after completing her doctorate in English literature in 2012, Dr. Miller is now preparing to start her own life-coaching business.

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A HANDFUL of professors at Stanford, sensitive to the exploitative potential of graduate school but convinced of its value, are trying to instigate meaningful change. Last year, six of them wrote “The Future of the Humanities Ph.D. at Stanford,” a much-discussed white paper promoting the redesign of curriculums to prepare humanities Ph.D.’s for “a diverse array of meaningful, socially productive and personally rewarding careers within and outside the academy,” as well as reducing time to degree, which often takes close to a decade.

Russell A. Berman, a German professor and an author of the paper, feels a responsibility to recognize these practical exigencies. “Graduate education is primarily an intellectual undertaking,” he said. “But most of the participants are at an age where they also have to be making career choices.” He added, “The academic job market is so weak that it just can’t be business as usual for department faculty.”

And yet he does not buy into the popular notion that there are just too many Ph.D.’s. “I think that doctoral education is good for individuals who are passionate about the topic,” Dr. Berman said. “I think it’s good for society. They contribute in lots of different ways.”

The professors called on Stanford to offer supplementary funds to departments that devised plans for alternative career preparations and shortening time to degree. The School of Humanities and Sciences requested proposals, but few departments responded. At the same time, new programs have been set up to help link humanities Ph.D. students with jobs in Silicon Valley and in high schools.

Initiatives are afoot at other schools as well. Collectively, they could begin to alter expectations.

While not grappling with the same existential questions as humanities programs, the Polytechnic Institute of New York University is trying to expand career options for its Ph.D. candidates. It has opened two incubators over the last few years, with a third to open soon, offering space, legal services and marketing advice to facilitate entrepreneurship. The draw, according to Kurt H. Becker, associate provost for research and technology, is “a career path that would allow them to be much more in control than if you’re a postdoc or an assistant professor, where your career path is pretty much mapped out.”

The Praxis Network consists of “digital humanities” initiatives at eight universities, focusing primarily on graduate education. They aim to prepare students for roles outside the professoriate, stressing skills like collaboration, technology and project management. Students in the Digital Fellows Program at the City University of New York Graduate Center, in its second year, commit 15 hours a week to a selected project and related activities. One historian completed a project called “Data Mining Diplomacy: A Computational Analysis of the State Department’s Foreign Policy Files.” Fellows also design Web sites and organize a workshop series for other students, all of which is far removed from the traditional humanities experience of sitting alone in a room with a stack of books.

“We are really thinking about it as a kind of laboratory for reshaping doctoral education and rethinking the kind of skills that we give our students,” said Matthew K. Gold, an English professor who runs the program.

Ethan Watrall, a professor of anthropology at Michigan State University, runs the Cultural Heritage Informatics Initiative as part of Praxis. “I try to destigmatize this idea of not going on to a tenure-track job,” he said. “It doesn’t matter — who cares? If you’re happy and that’s what you want to do, that’s awesome.”

He believes the culture has begun to change, “mostly because of the sort of desperate need for it to change.”

Still, he said, a transformation is only beginning. “The academy is a big ship and it takes a long time to turn it.”

Almost two years ago, pregnant with my daughter, I paid my first visit to the Cambridge Birth Center. Located inside an old Victorian house, the facility is hard to distinguish from a modestly appointed home, with blond wood floors and three spacious bedrooms, each attached to a bathroom with a large tub. If the interior is comforting, so is the view: the Cambridge Hospital, part of the same campus, is visible through most windows. Should you need to get there in a hurry, the trip would take about ten seconds.

Like most of my fellow patients, I chose the birth center because I wanted to avoid the high-tech approach typical of hospitals, but I didn’t feel entirely at ease with the idea of a home birth. The birth center hit the sweet spot. I loved the cozy environment designed expressly with birth in mind. I adored my unflappable midwife, Heidi, a genius at deflating anxieties. And when in labor, I benefited from the warmth and expertise of the midwife on call, Connie, who calmly coached me through delivery.

But I didn’t realize until later that there were other reasons to love birth centers—namely, hard economics. In light of this week’s big Times article on the staggering costs of maternity care in the United States, it’s time that birth centers receive the recognition they deserve as a viable alternative. A recent major study confirmed that for low-risk pregnancies, birth centers provide equally safe care for much lower costs than hospitals. Even the Affordable Care Act acknowledges their value; a little-noticed provision of the law mandates that Medicaid cover birth center services. Yet, thanks to a combination of unfriendly laws in some states, insurer resistance, and lack of public awareness, far too few American women have access to this form of excellent, cost-effective maternity care.

First, to clarify the terminology: a free-standing birth center is a homelike, midwife-led facility that offers prenatal care and delivery services and has emergency arrangements with a hospital. It can be located inside a hospital, but it must be separate from the acute obstetric care unit. (Some hospitals use the term “birth center” to describe conventional units, which has caused confusion.) Distance from the hospital varies. I must admit I would have felt much less comfortable with a more remote hospital. But in some rural areas, women live hours away from the nearest one, and it may be preferable to have a facility closer to their homes than to the hospital. All birth centers monitor patients throughout pregnancy to ensure that they are low-risk; if not, they are referred to hospitals.

According to the American Association of Birth Centers, the facilities operate according to the “wellness model” of pregnancy and birth, as opposed to the medical model that sometimes seems to treat these events like illnesses. As AABC executive director Kate Bauer told me, “In a hospital, all women are treated as if they are high-risk. In a birth center, every woman is seen as low-risk, unless her risk level is elevated…It’s appropriate use of resources.” You can’t get an epidural at a birth center. They rely on low-tech pain-management techniques such as warm baths and changing position, though some do offer conservative doses of Demerol and nitrous oxide.

That birth centers offer safe, economical care is not news. A landmark 1989 New England Journal of Medicine study reviewed records of 11,814 women at 84 birth centers and found that there were no maternal deaths, while the neonatal mortality rate was similar to that of low-risk hospital births. The rate of cesarean sections (which involved transfers to hospitals) was 4.4 percent. The article concluded, “Few innovations in health service promise lower cost, greater availability, and a high degree of satisfaction with a comparable degree of safety. The results of this study suggest that modern birth centers can identify women who are at low risk of obstetrical complications and can care for them in a way that provides these benefits.” (The authors emphasized that all of the birth centers in the study were accredited; the safety of unaccredited centers is uncertain.)

A new study published in January in the Journal of Midwifery & Women’s Health ratified those results. Because safety is such a concern, allow me to dwell again on the numbers. This study reviewed the records of 15,574 women at 79 birth centers from 2007 to 2010. Again there were no maternal deaths, and again the neonatal mortality was comparable to low-risk births in hospitals. Just 6 percent of the women ended up having cesareans at affiliated hospitals, compared with about 25 percent of low-risk women who started out at hospitals. (The total nationwide rate of cesareans in 2010 was 32.8 percent.) The study estimated that given the lower cost of the facilities, and the much less frequent interventions, these birth-center deliveries saved approximately $30 million.

Despite these positive outcomes, only a tiny minority of women (.3 percent in 2010, according to the CDC) give birth in such centers. The AABC estimates that if just 10 percent of the 4 million women who give birth annually did so in birth centers, the savings would come to at least $2.6 billion. The provision in the Affordable Care Act—stipulating that Medicaid programs reimburse birth centers—was included because it was projected to save money.

By some indications, trends are favoring birth centers. According to the AABC, their numbers have grown from 170 in 2004 to 251 today. Forty-one states license birth centers, the American Public Health Association has issued guidelines for licensure, an entity called the Commission for the Accreditation of Birth Centers does what its name suggests, and the AABC also has standards for members. All of this constitutes what the recent journal article calls an “infrastructure of standards, accreditation, and licensure” that contributes to the safety and reliability of accredited centers.

Historically, tensions have simmered between the midwife community and ob-gyns, but even the American College of Obstetricians and Gynecologists has endorsed birth centers—albeit in a somewhat roundabout manner. In a 2008 statement reiterating their strong opposition to home births, ACOG asserted that delivery “in a hospital or accredited birthing center is essential” (emphasis mine).

Birth center advocates were also thrilled by the Medicaid provision in the health care reform law, sponsored by Senator Barbara Boxer: not only should it mean expanded birth center coverage for low-income women, but private insurance often takes its cues from the federal programs, so a ripple effect is conceivable. Now, despite the potential savings, private insurance often resists covering birth centers. (I was fortunate on this front: my total out-of-pocket expenditure was a $15 co-payment for my first prenatal appointment.)

But amid this progress, serious gaps remain. Nine states do not license birth centers, and the Medicaid provision applies only to those who do. The AABC claims, too, that some states have not properly implemented this part of the law. State laws vary widely, with some much more hospitable to birth centers than others. These differences don’t always break down according to familiar patterns: In Texas, for instance, birth centers flourish, while Maine does not license them.

As a result, many women who would prefer birth centers don’t have the option—and many of these end up having c-sections and other interventions in hospitals. I blame not greed or evil but the so-called law of the instrument: the tendency to rely on the tools you have. The debate about childbirth is particularly polarized—with some convinced that pregnancy should not be treated as a medical condition—but not unique. Take mental health. If you suffer from anxiety and you go to a psychiatrist, you will likely leave with a prescription in hand. Some people know they want Zoloft, but others would like to try a less medical approach first.

A final obstacle for birth centers in reaching their full potential is cultural. The majority of women seem to think that birth centers are a risky option for a hippie fringe, one step removed from giving birth in a field under a full moon, orgasmically. Granted, birth centers will never be right for everyone. I know women who don’t see the point of trying to give birth without an epidural. (As writer Anne Lamott memorably put it: “I have girlfriends who had their babies through natural childbirth—no drugs, no spinal, no nothing—and they secretly think they had a more honest birth experience, but I think the epidural is right up there with the most important breakthroughs in the West, like the Salk polio vaccine and salad bars in supermarkets.”) Then there are women who wouldn’t consider leaving the privacy and comfort of their own home to have a baby. But there’s a good-sized contingent that wants to try for a low-tech birth in a relaxed setting that’s been proven safe. Birth centers are more likely to provide this experience than hospitals are. They should be seen not as sites for New-Age-y, hazardous adventures, but as places that offer mainstream, high-quality maternity care.

One last advantage of birth centers: the parties. The Cambridge Birth Center has thrown two afternoon shindigs for families since my daughter was born last July. She got to meet the midwife who listened to her heartbeat in utero, and the one who delivered her, as well as other kids who were born there. And I got to return again to the place I’d visited so frequently, this time eating chips and salsa.

When my parents married in 1977, women’s liberation was in full swing and my mother was a consciousness-raiser. She was about as likely to take my father’s name as she was to sport a veil at the wedding. She would remain Ms. Tuhus. Nine months later, the surname for their new baby (me) was self-evident. My parents yoked their names into a new one: Tuhus-Dubrow.

“I knew that was the best I could do,” my father told me. “As opposed to just Tuhus.”

Other parents, albeit a small minority, had the same idea. By the mid-1970s more women were keeping their maiden names, so hyphenating the names of the children seemed like the next logical raspberry to blow at the patriarchy, a stand against the family’s historical swallowing up of women’s identity.

Hyphenation has other pluses. The invented names are distinctive; I’ve never come across a Tuhus-Dubrow outside my immediate family. The inconveniences — blank stares, egregious misspellings — are outweighed by the blessing of never having to worry about a Google doppelgänger.

The problem, of course, is that this naming practice is unsustainable. (Growing up, I constantly fielded the question, “What will you do if you marry someone else with two last names? Will your kids have four names?”) Like many of the baby boomers’ utopian impulses, it eventually had to run up against practical constraints.

I don’t have children yet, but plenty of others in my cohort — the first in which nontrivial numbers were born hyphenated — do. And reproducing while hyphenated brings inevitable quandaries. I was curious to see how my peers have handled them. So I asked around. What I found was a whole gamut of solutions. The name-blending pioneers now have grandchildren whose names embody an intriguing mix of the traditional and the maverick.

I encountered several women who kept their own hyphenated names when they married, but gave their children the father’s surname. This scenario seems to deviate the least from the mainstream: after all, many other women with single surnames do the same.

Zoe Segal-Reichlin, 33, a lawyer for Planned Parenthood in New York, was typical in her approach to naming her son, now 10 months old. She said she flirted with alternatives: hyphenating three names, picking either Segal or Reichlin to link with her husband’s name. But ultimately, none felt quite right, and going with the father’s name won out as the most practical choice.

“It was the best of bad options,” she told me.

Same-sex couples face their own quandaries, since there is no tradition to follow. Cora Jeyadame (née Stubbs-Dame), 37, a first-grade teacher in Newton, Mass., was determined to share a name with her child, and to think ahead more than her own parents had.

“It’s a one-generation solution,” she said of hyphenation. She and her wife, whose surname was Jeyapalan, spliced their names together into an entirely new, hyphenless amalgam.

How did they decide on the name? “I actually put it out on Facebook,” she said: “ ‘I challenge you to come up with good combinations.’ ” The winning entry, Jeyadame, is the legal surname of Cora and her 4-month-old; her wife uses it socially.

Naming decisions raise novel questions for hyphenated men. There is little precedent of husbands changing their names at marriage or giving up the prerogative to pass their names on. Traditional practices grew out of a male-dominated culture and a need for simple rules. But there is another, less obvious motive: to hold men accountable for their offspring.

“How do you attach men to children?” said Laurie K. Scheuble, a senior lecturer at Pennsylvania State University who has done several studies on naming practices. Names are “a very functional and practical way” to do so.

But perhaps, in an age when men wear BabyBjorns, it is no longer always necessary. When Daniel Pollack-Pelzner, 32, an English professor who lives in Portland, Ore., married Laura Rosenbaum, he toyed with the idea of a creative synthesis.

But “Rosenpollackpelznerbaum sounded like a weapon of mass destruction,” he said. When they had a son, giving him Daniel’s last name seemed too complicated, so they gave the baby Laura’s.

Mr. Pollack-Pelzner initially worried that having a different name would arouse suspicions, leading to airport frisks and other indignities. But since his son was born, “I’ve hardly thought about it at all.” No one has ever challenged whether he is the toddler’s father: “The poor guy is cursed to look just like me.”

Nathan Lamarre-Vincent and his wife, Sarah Miller, went the opposite direction, giving their children Nathan’s hyphenated name. Mr. Lamarre-Vincent, a 34-year-old Harvard postdoctoral fellow in molecular biology, said it was a default decision: “We were both kind of go-with-the-flow,” he said, and simply hewed to tradition.

The irony is that the name is the product of his own parents’ defiance of that tradition. It is a little like following every step of an old-school Thanksgiving recipe, but starting out with a Tofurky.

In a 2002 paper, Ms. Scheuble and her husband, David R. Johnson, a Penn State professor, predicted that the importance of a family name could begin to decline. Thanks to more divorce, remarriage, same-sex unions and retention of maiden names, it is far from unusual for members of the same nuclear family to bear different surnames.

Nevertheless, the vast majority of families stick with custom. According to a 2009 study analyzing data from 2004, only 6 percent of native-born American married women had unconventional surnames (meaning they kept their birth names, hyphenated with their husbands’ names, or pulled a Hillary Rodham Clinton).

I know lots of women, including myself, who kept their birth names at marriage. But according to my anecdotal observations, which others seconded, rates of hyphenation seem to have fallen since my brother and I were born.

As Ms. Segal-Reichlin said, “At the time I think they thought they were going to be the wave of the future,” but it has not panned out that way. Still, hyphenated names are not entirely a relic of the ’70s, like sideburns and lava lamps: witness the Jolie-Pitts.

Based on my conversations, the verdict on hyphenation was mixed.

“When I was young I hated it,” said Sarah Schindler-Williams, a 32-year-old lawyer in Philadelphia. “It was long, it never fit in anything. I was always Sarah Schindler-Willi.”

But most, including Ms. Schindler-Williams, eventually grew to appreciate their cumbersome monikers. Names frequently convey information about their bearers: Weinberg or O’Malley gives you a hint about the person attached to it. But conjoined names, several people mentioned, also say something extra about your parents’ egalitarian values. (Unless you are British; then it means you’re posh.)

What did our parents expect us to do when we reached this stage of our lives? They trusted it would all work out somehow. As Ms. Segal-Reichlin’s parents told her, “We figured that was your problem.”

The coral reefs of Hawaii are enchanting: a full spectrum of brilliant colors, teeming with spiky urchins, striped damselfish, sluggish sea cucumbers, and hundreds of other creatures. Many of these species are found nowhere else in the world, and the ecosystem’s uniqueness makes it a darling of oceanographers. Researchers, Hawaiian residents, and visiting snorkelers can all agree: The reefs are a priceless treasure, and their disappearance would constitute an incalculable loss.

But Hawaii’s reefs are more than just photogenic seascapes with sentimental value; they’re economic powerhouses. They provide a suite of quantifiable benefits to Hawaiian society, through fisheries, tourism revenue, and their role as a buffer against wave erosion and tropical storms. The authors of one study collected a mass of data — ranging from fishery income to the cost of renting masks and fins — and placed the value of the reefs at a minimum of $360 million per year. To thoughtlessly damage a coral polyp, in this view, is tantamount to shredding a $20 bill.

A growing number of environmentalists, scientists, and economists have embraced the concept of putting a price tag on nature, which is reframed as “natural capital” and “ecosystem services.” Rather than casting nature as some abstract, awe-inspiring entity, or as a luxury trumped by economic imperatives, they see it as a provider of an array of specific, identifiable services that are vital to our well-being. And increasingly, they are deploying sophisticated methods to arrive at precise and credible dollar values. They hope that their painstaking analyses will lead to smarter decisions about land and water management. And, more broadly, the thinking is that hard numbers will resonate more than odes to Mother Earth — that dollar figures will allow people to better understand their own reliance on natural goods and services, as well as the costs of neglecting or destroying them.

“The value that nature delivers to us is economically invisible,” says Pavan Sukhdev, study leader of a UN-sponsored report on The Economics of Ecosystems and Biodiversity. “Effectively we pretend that it’s zero. The point is, it’s there.”

In recent years, this approach has gained a foothold in academia, international institutions, and a number of governments. In the United States, China, Costa Rica, and elsewhere, governments have opted to fund the preservation of forests, watersheds, and other ecosystems — and not because, or not only because, of their beauty. The primary impetus, rather, is the “services” they provide, including air and water purification, carbon sequestration, flood control, and drought prevention. The World Bank has sponsored numerous relevant projects, and a Stanford-based initiative, the Natural Capital Project, draws together environmental organizations and academics to advance and implement the idea.

And yet, for all of the obvious appeal of this approach to green types, there are serious concerns about translating ecological value into dollars and cents. Commodifying nature offends the sensibilities of some environmentalists, who believe we should prize it for its intrinsic worth, and for ethical and historical reasons. If we appraise nature only for the “services” it provides to humans, could that lead to an overly anthropocentric ethos that jettisons any elements that do not obviously accrue to our benefit? Several years ago, Douglas McCauley, a doctoral candidate in Stanford University’s biology department, published a much-discussed Nature commentary, in which he stressed the dangers of relying too heavily on this model.

“Ecosystems were not made to serve people,” McCauley wrote in an e-mail from Kenya. “I worry about teaching children and legislators to protect nature *because of* these services. How will generations raised on this message treat costly panda bears, worthless butterflies, or forests whose water purification services have been replaced by human innovation?…I think there are bigger and better reasons to protect nature.”

Most advocates of monetary valuation acknowledge that it cannot constitute the sole basis for conservation; it supplements other, less tangible rationales. (At the same time, some assessments do try to account for those bigger, better reasons, classified as “cultural services,” which include aesthetic and spiritual value.) But proponents insist that without this additional tool in the conservationists’ arsenal, ecological disaster awaits — policy makers deal in numbers and dollars, so pragmatic environmentalists must speak that language too.

As Gretchen Daily, a Stanford biology professor and chair of the Natural Capital Project, puts it, “Conservation, using traditional approaches, is utterly doomed to fail.”

…

Some parts of nature, of course, have long had prices: Timber, salmon, blueberries, and other goods have a market value. But efforts to place a price on natural services with no market value began to take shape in the 1970s and 1980s. This period saw the advent of a field called “ecological economics,” in which scientists and social scientists attempted to reconcile two disciplines that were often at odds. In 1997, some of this work culminated in a seminal Nature paper by Robert Costanza, then a professor at the University of Maryland, and others. The paper estimated the value of the earth’s natural capital to be an average of $33 trillion per year, as compared with a global gross national product of about $18 trillion. Reflecting on natural capital’s indispensability to the world economy, the authors suggested that it should be factored into everything from national accounting systems to commodity prices.

In the mission to valuate nature, there are two distinct but complementary tacks. Calculating the global or national value of natural capital is a fundamentally “rhetorical” exercise, as Duke University law professor James Salzman notes; the point is to convey in a forceful, concrete manner the enormous worth of these assets. The other approach, which has gained currency recently, is much more practically oriented: to try to assess the economic outcomes of different interventions in specific places, in order to manage land and water more wisely.

So how do you assign a dollar value to something as nebulous and unpredictable as nature? It’s not easy, but a variety of methods have emerged. One relatively straightforward strategy is to make a direct comparison to alternative scenarios. What cost would be incurred — in the form of natural disaster, lost income, etc. — by the degradation of, say, a wetland, which offers water filtration and flood protection? Or a forest, whose benefits include carbon storage, air and water purification, timber, and fuel wood? Similarly, how much would it cost to create a technological substitute for, say, clean drinking water, such as a filtration plant? Or a levee to replace mangroves as flood buffers?

“If we were to provide that service, is it cheaper to provide it with landscape management?” asks Salzman, who is involved in the Natural Capital Project. “You can provide it through built capital or you can provide it through natural capital.”

Assessments of more amorphous value can be made by proxies. For example, you can compare housing prices near a beach or a mountain range to similar houses in a different locale. This, in theory, provides a clue about the implicit value homeowners place on the natural area. Similarly, the “travel cost method” looks at what visitors pay to enjoy a site in terms of transportation expenditures and time. The “contingent valuation” method surveys people about how much they are willing to pay for a given ecosystem service.

Of course, daunting challenges arise. First are the scientific ones: Ecosystems are complex, dynamic affairs, subject to so-called feedback and threshold mechanisms, in which abrupt, unforeseen changes take place. It is often exceedingly difficult to predict how an intervention will affect the multiple, interacting services at stake. Then there is the task of translation into monetary values. The method of surveying people depends on their opinion of the value — and part of the problem is limited awareness of that value, as Costanza, now at Portland State University, points out. (On the other hand, such surveys entail no actual financial sacrifice, so the answers could be artificially generous.) There are also difficult ethical questions, regarding, for instance, how much weight to give present versus future benefits. Stefano Pagiola, an economist at the World Bank’s Sustainable Development Department, says the field is “polluted with bad estimates.”

Despite the hurdles, there are now a number of projects underway throughout the globe, often under the rubric of “payment for ecosystem services.” Not all of them attempt to rigorously determine the monetary value of the services; they simply recognize the economic benefits of conservation, and offer some financial reward on that basis.

One of the most celebrated examples is in New York City, which gets most of its water from the Catskill/Delaware watershed. By conserving land upstream — through acquisitions and payments to landowners — the city has avoided the need to build a new filtration plant, which would cost billions of dollars. Most recently in 2007, the city pledged $300 million over 10 years to these investments. Within the past two years, Santa Fe and Denver have opted for similar policies, as the news source Ecosystem Marketplace has reported. In China, devastating floods and drought in the late 1990s spurred leaders to take action, when they realized deforestation was a primary culprit. (Forests absorb and slowly release rainwater, providing the “services” of flood and drought prevention.) They launched initiatives, still ongoing, to pay villagers to conserve forests and to convert cropland back to forest and grasslands. Costa Rica also has a longstanding program paying landowners to conserve and restore forests.

A few models are emerging to try to calculate reliable, meaningful dollar values. One, in development by the Natural Capital Project, is called InVEST, for Integrated Valuation of Ecosystem Services and Tradeoffs. The software analyzes the benefits of services like water quality and quantity, erosion control, carbon sequestration, and pollination. It models alternative scenarios to inform users how ecosystem services would be affected, presenting outcomes in the form of maps, balance sheets, and “tradeoff curves.” The results show both tradeoffs and synergies between different services — so that, ideally, policy makers might choose to prioritize the areas that maximize useful service provision. At least four “water fund” projects in South America — in which downstream users, including a hydropower company and a beer bottling business, pay people upstream to keep the water clean — are using InVEST. The Natural Capital Project is working with Google to make it freely available on the Internet. Other new tools — two prominent examples are EcoMetrix and ARIES — have similar aims.

But even as these techniques become increasingly refined, they will not suffice to effect the widespread change their inventors are seeking. Only in certain cases will crunching the numbers show conservation to be the fiscally obvious choice. For example, in the absence of a carbon tax or a cap-and-trade policy, the tools can calculate the social value of carbon storage, which would mean long-term economic savings for society at large. They can’t, however, claim that carbon storage has a current monetary value for an individual company or municipality or private landowner.

“I don’t want to be too cynical,” says Steve Polasky, an economist at the University of Minnesota who works on InVEST. He acknowledges that some people would consider the social value seriously, but “the cynical part of me says, you know, you really do have to have the right set of incentives in place.”

…

The development of these tools and the proliferation of related projects have occurred against the backdrop of a broader philosophical shift in environmentalism. Historically, conservationists had sought to fence off pristine wilderness, protecting it from any human interference. Over the past few decades, the ethos has evolved to emphasize the interdependence of humanity and nature. In part, this is sheer realism: With a global population nearing 7 billion, people have to find ways to live in concert with nature. This newer focus also stems from the recognition that human survival depends directly on healthy ecosystems. Not incidentally, it also happens to be seen as a more effective way of selling conservation to those who are disinclined to be tree-huggers — i.e. it’s not just for the cute and furry animals, it’s essential to us, too.

But this more utilitarian view — nature as handmaiden to human well-being — has elicited skepticism. One critique questions its accuracy. Mark Sagoff, director of the Institute for Philosophy and Public Policy at George Mason University, has written that “we benefit from nature not by preserving but by ‘improving’ it — for example, by plowing a field, building a road, constructing a house, drilling a well, damming a river, farming a salmon or oyster, or altering a genome.” He has challenged the received wisdom about New York’s water plan, pointing out that the city uses chlorine to disinfect the water, and that one of the greatest sources of pollution is fecal matter from wildlife.

The utilitarianism also troubles some environmentalists: What happens when the filtration plant becomes cheaper than conservation easements? These environmentalists hold dear the useless magnificence of nature, its bizarreness and its fearsomeness, whether in the funny face of a snub-nosed monkey or the dizzyingly precipitous walls of a canyon. The value they perceive resists quantification — even in the form of “cultural services.”

And yet, they see that older approaches have left the environment deeply vulnerable. The greatest weakness of pricing nature — its kinship with market ideology — is also its greatest strength.

Douglas Kysar, a Yale law professor and author of the book “Regulating from Nowhere: Environmental Law and the Search for Objectivity,” expresses what may be a common ambivalence — wary in theory, resigned in practice. “We used to have this idea of being humbled by nature, being awestruck by its ability to exceed our comprehension, to exceed our mastery,” he says. He worries that the logic of ecosystem services “reinforces a deeper mindset that is very much in tension with the needs of ecology.”

But on an immediate, practical level, he supports the efforts as far preferable to the status quo. “It fits with the dominant ideology — and if you can’t beat ’em, join ’em.”

This past week, wrangling over the Bush-era tax cuts has riveted Washington. The spectacle is only the latest round in an endless debate, one that has launched innumerable op-eds, cacophonous talk-show segments, and dinner-table quarrels. As conservatives see it, higher tax rates hurt job creation as well as undercut the incentive for entrepreneurship and hard work. Many liberals cast these downsides as modest, while stressing the value of tax revenue. Will tax cuts bring a bloom of free enterprise — or exploding deficits? Economists have studied the issue ad nauseam, but firm conclusions are elusive. It is difficult to tease out cause and effect, because at any given time, economic conditions other than taxation also shape behavior.

If only there were a scientific way to determine the real impact of taxation on industriousness, labor supply, and innovation.

According to some scholars, there is. Randomly assign a representative sample of the population — say, 10,000 taxpayers — a lower tax rate, and see what happens. Did these Americans, on average, behave any differently than their counterparts? Did they work longer hours or more jobs, start more businesses, hire more employees?

In other words, test government policies using the same technique — randomized controlled trials — used to test new drugs. A growing chorus of legal scholars, economists, and political scientists believes that such trials should be conducted to evaluate a wide range of laws: gun control, safety and environmental regulations, election reforms, securities rules, and many others. And some believe that we are ethically obligated to do this, because laws affect our lives so pervasively. Understanding the true costs and benefits of legislation, they say, is essential to making good policy — and we may know much less about our own laws than we think.

“The randomized experiment is kind of the gold standard in medicine and social science,” says Ian Ayres, a Yale law professor and economist who advances the idea of the tax experiment in a forthcoming paper. “We should use that same tool to inform us whether laws work.”

Already, randomized trials have migrated beyond medicine. In recent years, experiments to test development programs in poor countries have grown common. Even in the United States, such trials have been used for several decades, in a scattered way, to evaluate social services such as job training and welfare reform, as well as criminal justice and education policies. In one controversial experiment described last week in The New York Times, New York City is testing a homelessness-prevention program by randomly denying services to some households. But now, proponents argue that this instrument should be used in other areas of law — that a culture of experimentation should take hold, and randomized trials should become the norm in lawmaking rather than the exception.

There are certainly potential problems with this vision. First is the question of effectiveness: In some cases, it may prove too difficult to run an accurate test. The full repercussions of laws often take years to manifest themselves, and small-scale experiments do not always translate well to larger settings. Also at issue is fairness. Americans expect to be treated equally under the law, and this approach, by definition, entails disparate treatment.

“The problem is, we’re dealing with laws that have a huge impact on people’s lives,” says Barry Friedman, a law professor at New York University. “These aren’t casual tests. It’s not, you try Tide or you try laundry detergent X….Here we’re talking about basic benefits and fundamental rights.” Though Friedman is sympathetic to the goal of gaining better empirical knowledge, he says, “My guess is some of it’s doable in some contexts, and a lot of it’s not doable in other contexts.”

But others are more sanguine, and they make the opposite argument: That precisely because the stakes are so high, the laws that we enact on a large-scale, long-term basis must be more rigorously tested. This wave of thinking is part of a broader trend in fields from health care to education: Our practices should be “evidence-based,” rather than deriving from theories and unproven assumptions. The question is whether this kind of scientific approach can successfully take on a project as unruly as our society — and our politics.

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The concept of randomized trials is usually traced back to the 1920s, when Ronald Fisher, a British geneticist and statistician, used the technique in agricultural trials. Fisher randomly assigned plots of land different fertilizers or crop varieties, and compared the results.

Before long, scientists began to apply the method to people. The virtue of randomization is that, provided the numbers are large enough, you can create two groups that are close to statistically identical — the same distribution of gender, age, height, educational background, and other characteristics. Any change in the treatment group can then be confidently attributed to the intervention, rather than to other factors. (In a variant of the concept, trials can randomly assign different interventions to multiple groups.) In observational studies, by contrast, it can be difficult to distinguish correlation from causation.

“The typical experiment involves very, very elementary statistical analysis,” says Donald Green, a Yale political scientist. “When things are done properly, you take the treatment group average and subtract the control group average. It could not be more simple.”

Randomized trials of drugs were first conducted in the late 1940s, and by the 1970s, they were widely used in the United States to evaluate new drugs. Now, of course, it’s unthinkable that the FDA would approve a new drug without clinical trials to show that it’s safe and effective.

The use of randomized trials outside medicine actually dates back even further, to a local experiment. In 1930s, the Cambridge/Somerville Youth Study, designed to reduce delinquency, randomly assigned over 500 boys to either a treatment group, which received visits from a counselor and other services, or a control group, which received neither. A 30-year follow-up found that the intervention had not diminished criminality and, strangely, seemed to have slightly exacerbated it. Since then, a number of comparable experiments have ensued. In the 1980s, police departments in Minneapolis and Milwaukee randomly assigned mandatory arrest for domestic violence offenders to assess its effect on recidivism. They initially found that arrest deterred future offenses, but over time a more complex picture emerged; particularly in areas with high unemployment, arrests appeared to provoke further battery. Similar state-run experiments have shown the effectiveness of unemployment programs that offer job-search assistance.

Though government has proved receptive to the idea in some areas, we are still far from the ideal envisioned by the most ardent proponents. They hope for a time when such experiments are the default. In the world they foresee, any politician who opposed a trial would be suspect, as resistance would appear to indicate lack of confidence in one’s position.

One promising area for expanding the use of trials is regulation. Michael Greenstone, an MIT economist, laid out this case in a chapter in the 2009 anthology New Perspectives on Regulation. While regulations profoundly affect everyday life, he argues, our system for assessing them is dreadfully inadequate. Regulations determine, he notes, the loans we can get, the kinds of materials we can use to build homes, the velocities of our vehicles, and the quality of our air and water. But they are typically evaluated, if at all, prospectively — when analysis amounts to educated guesswork.

We study regulations only at “the very moment when we know least about the consequences,” Greenstone says. “There is no culture of trying to understand ex post what the consequences are.”

As an alternative, he recommends introducing regulations on a small scale prior to rolling them out. Safety regulations, such as new rules for cars or cigarette lighters, could be randomly tried in some areas and evaluated after a designated period. If the benefits exceed the costs, they should be expanded; if not, they should be scrapped. Greenstone suggests that industrial plants could be randomly subjected to different environmental regulations. After a given amount of time, the air and water quality in the vicinity would be measured, along with health outcomes for people in the area and the effects on plants and animals. Various versions of regulations could be tried in different states or municipalities.

In a paper to be published in the University of Pennsylvania Law Review this spring, Yale professors Ayres and Yair Listokin and George Washington University law professor Michael Abramowicz advocate the systematic introduction of randomized trials throughout government — in legislatures and administrative agencies, at the state and federal level. They suggest that trials be “self-executing,” in that policies would be automatically enacted based on their results (though lawmakers would be able to overrule this default).

As proponents of this idea frequently note, Justice Louis Brandeis famously called the states the “laboratories of democracy,” but state-level innovations do not meet the standards of real, controlled experiments. Ayres and his coauthors propose that the federal government coordinate trials, randomly assigning states (provided they consent) to adopt certain laws; as Ayres puts it, “In the laboratory, you don’t let the rats design the experiments.” Another proposal, perhaps more realistic, is for states themselves to randomize across municipalities or counties.

There are concerns, of course, about how practical widespread tests would be. Some domains are more susceptible than others. Education policy, election laws, and criminology seem particularly ripe for randomized trials (and many have already been conducted, both by academics and government). In these realms, interventions are not likely to be obviously experiments. A kid in a class doesn’t know or care if his class size or teacher’s technique is part of an experiment. The same is probably true of a criminal who receives a particular sentence, or a voter who receives certain literature in the mail. Moreover, the outcomes are relatively conducive to measurement (test scores, recidivism rates, voter turnout). But in other cases, participating knowingly in an experiment could distort the result (this phenomenon even has a name, the Hawthorne effect). This problem could be especially acute for businesses that desire a particular outcome — such as lenient securities laws or safety regulations — and alter their behavior for the duration of the trial. And some experiments — such as giving individuals different tax rates — would surely be controversial. Finally, as even landmark trials like the domestic violence study underscore, the results do not always furnish clear-cut policy prescriptions.

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The essential goal here is to take the politics out of policymaking, to replace dogma with data. It’s a noble ideal. But society will always have to contend with clashing values and priorities. Gun control law, for example, may be quite conducive to experimentation. Virginia, say, could randomly assign counties to different restrictions, and measure crime rates over the next few years. But even if the trial demonstrated that gun control reduced crime, many people believe in the liberty to bear arms as a nonnegotiable right. If data showed that air and water pollution had no effect on human health, some would oppose the regulations on industry, while environmentalists would still support them. Good data can only get us so far.

The other obstacle involves the current state of our political discourse. Opponents of a law could still claim that the trial proved nothing. While academics consider it the gold standard, the public may not place more stock in it than in other kinds of research that are more easily manipulated. Already, suspicion of government is rampant, and opponents accuse the Obama administration of technocratic overreach. People don’t like to feel like guinea pigs, and states may chafe at playing the role of lab rats. It is easy to imagine that a substantial segment of the population would view randomized trials as nothing more than another elitist scheme.

That said, proponents of this idea don’t claim it’s a panacea. They do believe randomized controlled trials are, if imperfect, the best way we have of generating empirical data. In his recent essay, Greenstone argued for a “new era in regulatory reform.” The first era, he writes, was that of the New Deal and the Great Society, when the focus was on well-meaning efforts to remedy social problems. In Greenstone’s view, the effort seemed to count more than the results, with little emphasis on follow-up and evaluation. Then, in a backlash, came the second era, under the Reagan administration, when government was recast as the problem. Now, Greenstone believes, we must instigate a third era, in which government is neither demonized nor valorized, when results are measured meticulously and count for more than good intentions.

As Donald Green of Yale says, “We test pharmaceuticals because there are billions of dollars at stake, and lives.” The same, he argues, is true of our laws, yet we don’t subject them to the same scrutiny. “In some ways the question is, how badly do we want to know?”