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Gun violence and crime prevention. Smoking, alcoholism and gambling. Economic inequality and “winner-take-all” markets. During Philip Cook’s 44-year career at Duke’s Sanford School of Public Policy, he has studied some of our nation’s most intractable problems. His work produced entirely new ways to think about, and measure, society’s efforts to temper human excesses. The topics he studied drew him into politically charged debates, and at times, his email inbox was peppered with hate mail.

During those four decades, Cook held several key leadership roles at Sanford, helping build the program from a small interdisciplinary unit to a school enrolling more than 700 students each year. Cook arrived at Duke in 1973 just as the university launched its program in the nascent field of public policy studies.

This spring, Cook completed his final year of teaching, committee service, and administrative leadership and became one of the first emeritus professors of the school he helped create. At a festschrift in his honor, colleagues reflected on Cook’s “life of scholarship on bad behavior.” Bruce Kuniholm, Sanford’s first dean, called Cook the “intellectual godfather of the Sanford School.”


Kristin Goss (right), now an associate professor, was a student in Cook’s graduate statistics course. Later she became his research assistant, protégé, and co-author.

“He always asks the right questions ... (and) insists on rigor,” Goss said. “Phil wants to get the science right. He does that because he respects the scientific enterprise, but also because, in his line of work, people’s lives depend on getting the science right.”

Early Career Questions

Since the early days of his career, Cook has made a habit of asking questions others are not asking, and finding new ways to solve problems.

Robert H. Frank, Cook’s lifelong friend and co-author on the landmark 1995 book, The Winner Take-All Society, remembers him attending Berkeley on a National Science Foundation Fellowship, a bonafide math whiz. In the daily rivalry among economics PhD students to show who could master the hard math, Cook was “a blue chip contestant,” Frank said. He also had the “right stuff in terms of his family background -- one of his older brothers was a pioneering figure in computer science.”

More evidence of Cook’s aptitude came when he produced “A One-line’ Proof of the Slutsky Equation.” The equation – a staple of economics textbooks – is used to demonstrate the individual consumer’s reaction to a change in the market price of a commodity by breaking down the change in demand into substitution effects and income effects, Cook explained.


Cook in 1993.

“I was a TA for a graduate course in theory and was preparing notes for my section. I realized … when I do this particular manipulation, I can get this famous result in economics that typically requires pages and pages of proof. All of us who went through a PhD in economics at the time had suffered through these proofs, with lecturers at the blackboard for 30 minutes... I figured out I could do this very quickly …”

The proof became his first published paper in The American Economic Review. In his characteristically succinct style, Cook declared “the usual proof … very tedious and non-intuitive.” His solution was the opposite. Cook’s entire process is contained on page 139 of volume 62, 1972. It was, Frank said, “breathtakingly elegant.”

Over time, Cook’s solution not only made its way into U.S. textbooks, but also had global reach. More than 35 years later, when giving an invited talk in Santiago, Chile, Cook learned economics departments in Latin America had been teaching his proof for decades.

Crime and Opportunity

His dissertation, “The correctional carrot,” had a more applied bent. It examined the many obstacles released prisoners face when trying to land legitimate work, from employer discrimination to lack of education, and suggested public policies to improve the types of jobs available to them. The research combined labor economics with criminology, and ended up having a profound influence on his career: his first job offers came from both economics and public policy programs.

Cook was about to accept a job at the University of Pennsylvania when a phone call came in. Joel Fleishman, the first director of Duke’s Institute of Policy Sciences and Public Affairs, wanted to build criminal justice expertise at Duke. A friend had recommended Cook.

“It all came together,” Cook said. “There was the excitement of building a new program, and that appealed to me. It was not something I could have done in an economics department.”

Coming south also appealed to his wife, Judy, who later earned a PhD in clinical psychology at Duke.

Cook began following the work of University of Chicago economist and sociologist Gary Becker. Becker was a pioneer in applying economic analysis to all kinds of social policy issues, such as marriage and family formation, where economics had not been prominent.

“I have always been attracted to the humanistic elements of economics that tend to be underappreciated by the more high-testosterone economists."

Phil Cook

In one early foray into the humanistic potential of the dismal science, Cook tackled a thorny question of cost-benefit analysis. When considering how much to invest in a public policy or in insurance, how do you measure the value of “irreplaceable commodities” – things like human life, good health, family photos, and freedom of speech? Cook’s paper, written with Daniel Graham, advanced a new normative theory for valuing commodities that have no market substitutes.

The Weapon Matters


Gun Violence: The Real Costs (2000)

That work was an intellectual precursor for Gun Violence: The Real Costs (2000), coauthored with Jens Ludwig (above). Ludwig, a professor at the University of Chicago Harris School of Public Policy, directs the Crime Lab there and is Cook’s most frequent collaborator. They have written more than 40 papers together.


In Gun Violence, they developed a new way to calculate the toll of more than 75,000 shootings a year, coming up with an estimate of $80 billion in 1998. In addition to considering health care, criminal justice, lost wages and other “costs of injury,” they used the “contingent valuation” method to incorporate other costs into the equation – the costs of avoiding gun violence, for example. They did it by asking people what they would be willing to pay to reduce the likelihood of gun violence, which allowed them to develop an estimate of the value Americans place on safety. The book introduced a much broader way to think about the true costs of gun violence, moving the subject fully into the public health arena.

Although he has pursued many interests -- including his often-cited book on state lotteries, Selling Hope, with Sanford colleague Charles Clotfelter -- Cook is best known for his extensive work on weapons, violent crime, and criminal justice policy. Kristin Goss said Cook has had “a central role in building the field of gun studies,” with influential research on the role of firearms in injuries and death, how guns move in legal and illegal commerce – or secondary markets, as Cook named them – and the effects of background checks.

Throughout, a central idea in Cook’s research is that criminals are not born, but made, partly in response to both legal and illegal options available to them. An assault can easily turn into a murder if a gun is readily available. “It’s not about ‘character,’ but character interacting with opportunity,” Cook said.


Philip Cook and Charles Clotfelter in a publicity photo for their 1991 book, “Selling Hope: State Lotteries in America.”

Cook has served on expert panels dealing with school shootings, ballistics, the death penalty, juvenile justice and proactive policing. He also has shared his expertise with a Senate subcommittee and written numerous op-eds in national news outlets. His work inspired his friend Lisa Price, whose husband is U.S. Rep. David Price, to launch the nonprofit North Carolinians Against Gun Violence in 1993.

Study Guns, Make Enemies

Gun rights advocates see Cook as an adversary. They fill website comment sections with condemnations, and send him hostile email messages. The political and grassroots power of the National Rifle Association are formidable, he said, making “every court the NRA home court.” Whenever he speaks publicly about gun policy, Cook says he knows he will be punished – an experience all gun researchers share.

Supporters of increased gun regulation haven’t always welcomed his findings, either.

After the Brady Law was enacted in 1994 – a hard-fought victory for gun violence prevention advocates that created a waiting period and background checks – those advocates were dismayed when Cook’s and Ludwig’s review showed that -- at least at first -- gun-related homicides were unaffected by the new law, which they said did not go far enough. Even the Clinton Administration challenged the conclusion.

“Phil has an absolute laser-like focus on following the data were they lead, without fear or favor,” Goss says.

Because guns are everywhere, and in movies and on TV, getting people to believe any scientific evidence about them is a hard sell, Cook said. For example, use of a gun for self-defense is rare and gun suicides are more common than homicides, but that is not the narrative we know best.

“People believe that having a gun is useful [for self-defense] because they have seen it a thousand times [on TV]. Someone is able to save the day because they shoot somebody else. Our political process reinforces this false belief."

Phil Cook

In 2014, Cook and Goss drew on their combined 60 years of work on gun violence field to coauthor The Gun Debate: What Everyone Needs to Know. In just 220 pages, they debunked misconceptions and answered hundreds of historical, political, economic, public health, cultural and regulatory questions about the 200 to 300 million guns in America.

Alcohol and Taxes

Cook’s gun research led to his selection for a 1978 National Academy of Sciences expert panel – the first of more than a dozen expert panels he has served on – to examine alcohol control. Both alcohol and guns are legal, regulated products whose misuse can have fatal consequences, and the organizers thought Cook’s perspectives and methods might transfer. He was one of the few economists on the panel chaired by Harvard Kennedy School Professor Mark Moore.

Cook began to wonder if higher prices could reduce alcoholism. The consensus answer in the late 1970s and early ’80s was “no.” In fact, the suggestion was habitually dismissed as neo-Prohibitionist and ineffective, Cook said, “as if that were the end of it.”

At the time, psychologists and addiction experts were fighting the notion that alcoholism is a moral failing. They were making the case that excessive drinking is a compulsion and a complex health problem, and public policy was focused on alcoholics. The possibility that higher prices might significantly influence their drinking wasn’t even being studied.


Phil Cook and North Carolina Governor Jim Martin (‘85-93)

In 1982, Cook and Duke economist George Tauchen wrote “The effect of liquor taxes on heavy drinking,” providing the strongest evidence to date that raising taxes did, in fact, reduce death rates due to chronic drinking. They used death rates from cirrhosis of liver as a proxy measure of heavy drinking.

“When I first looked at the effect of liquor taxes on cirrhosis mortality I did not have high expectations,” Cook said. “I remember sitting there and getting the first results and thinking, ‘by God it worked.’ “

Pioneering Methodologies

The way they arrived at the result was as significant as the finding. Because the 30 states they studied had many demographic and regulatory characteristics in common, yet had applied different tax rates, the states were, in effect, an experimental laboratory.

“We were the first to build that into a panel regression framework,” Cook said. Making use of a so-called “natural experiment” to evaluate policy change is now a common practice in the social sciences. Jens Ludwig called the shift to natural experiment research one of the two biggest changes in economics during his career, and “a critical step in making social science a little more like real science.”

However, for a variety of reasons, other economists ended up getting recognized for the innovation.

“But that’s okay. Life goes on,” Cook said. “It’s a common complaint in academia.”


Paying the Tab: the Costs and Benefits of Alcohol Control (2007)

In later studies, Cook showed how raising the legal drinking age and graduated driver license programs reduced drunk driving fatalities. His 2007 book Paying the Tab: the Costs and Benefits of Alcohol Control took a comprehensive look at U.S. alcohol laws and their effects. In particular he makes the case that alcohol taxes have not kept pace with taxes on other commodities that have unintended negative effects, such as tobacco. Nobel Laureate Thomas Schelling called the book “a masterly combination of analysis and evidence.”


Yet when it comes to policy reform, Cook said, “I’ve been on the losing side of the argument on this.” While the federal excise tax on cigarettes hit a historic high in the last decade, the tax on beer, wine and liquor has declined over the last 50 years and there is little interest in reversing that trend. “Alcohol distributors are one of the most powerful lobbies in every statehouse and in Congress,” he said.

Nevertheless, Cook is glad to see the public health community has embraced the idea that “price matters” – for tobacco, for firearms, and for alcohol.

“There almost seems to be an international consensus, and I can tell you in 1980 there was no such consensus. It was seen as laughable.”

Winners Take It All

Cook’s research – in more than 200 articles and four major books -- has been cited more than 16,400 times. Topping the list is a book about neither crime nor alcohol: The Winner Take-All Society: Why the few at the top get so much more than the rest of us. He and Robert Frank co-authored the book in 1995 and republished it with a new forward in 2010. It was named a New York Times notable book and a best book of the year by Business Week and China Times. It was translated into Chinese, Portuguese, Korean and Japanese.


The Winner-Take-All Society (2010)

The book had its roots in a walk across campus. Cook remembers being struck by how often he saw students wearing paraphernalia emblazoned with the Duke name.

They were proud to attend an elite school and wanted to tell the world. His research documented a trend he saw reflected in students’ attire: the top students were no longer choosing a wide variety of schools, including in-state schools. Instead, they were mostly funneling into elite institutions.


Cook and Frank went on to document how, beginning in the 1970s, the top 1 percent of earners began collecting an ever-growing share of the nation’s earnings growth. Open trade and technology were fueling a rising economic tide. But rather than lifting all boats, Cook said, the tide was lifting, “mostly yachts.”

A root cause of the inequality, they said, was the expansion of “winner-take-all” markets in sports, business, entertainment and education – where many people participate but the winners rake in a vastly disproportionate share of the spoils.

“Unlike virtually all other economists, we con­clude that rising inequality is more likely to curtail than to stimulate economic growth,” the authors wrote.

Today, Frank says most of their predictions about the effects of income concentration have come true. Income and wealth inequality are top political issues, “the other 99 percent” is a social media catchphrase, and Frank and Cook’s 22-year-old book seems prescient.

Crime, Endlessly Fascinating

Now, Cook’s research again focuses on crime, in particular the role of private companies in crime prevention.

“The fact that there are more private security guards than there are uniformed police officers should get somebody’s attention,” but to an extraordinary extent, this area is ignored, he said. “All of the talk about crime is about government and law enforcement.”

Cook also is returning to a topic he first studied in 1974: the role of witnesses and victims who voluntarily come forward, usually without compensation, to testify and help police solve crimes. The research, with Braga and others, is in progress in Durham and Boston. The third city will be Chicago.

In Durham, only 10 percent of nonfatal shootings result in an arrest. In Chicago, it’s 5 percent. With numbers like that, people know, “In Durham or Chicago, you can shoot someone with impunity.”

“In each city one of the goals is to measure the contribution of additional inputs into the outcome of interest, which is clearance by arrest or conviction,” Cook said. “Say, for example, you put in an extra $10,000 per case, could you increase the clearance rate from 10 percent to 15 percent?

Building Sanford: Program, Institute, School

Four decades ago, Sanford was a handful of faculty, most in their 20s, “making stuff up” as they went along -- a “children’s crusade” – Cook said. The Sanford trailblazers – Joel Fleishman, James Vaupel, Bruce Payne, Bill Hawley and others – had no senior scholars to advise them on their careers. In 1974, the first graduating class consisted of eight undergraduate majors.

Cook helped develop the master’s degree program in public policy, served as director of the Institute of Policy Sciences and Public Affairs from 1985-89, and led the institute again from 1997-99. When the institute took another leap forward to become Duke’s tenth school in 2009, Cook took on the new role of senior associate dean, directing faculty and research.

At the end of Cook’s first stint as director, Clotfelter praised his ability “to play the traditional chairmanly roles of cheerleader, advocate, father confessor; and the uniquely directorial roles of academic entrepreneur, university statesman, and international diplomat” -- all while “disarmingly encased in a modest and approachable exterior.”

By 2017, the graduating class numbered 202, along with more than 100 master’s and PhD graduates. Today, young faculty join “a fully formed institution with two buildings, a full array of degrees, and 70-plus faculty members,” Cook says, “and mostly everything has been decided. It is an entirely different experience building your career.”

The criminal justice concentration that initially led Joel Fleishman to recruit Cook did not materialize. An early hire in that area, Daniel Nagin, left Duke for Carnegie Mellon and became one of the world’s leading criminologists. Cook collaborated with Nagin, Ludwig, Anthony Braga -- director of the School of Criminology and Criminal Justice at Northeastern University – and many others, but has not had other criminal justice scholars close at hand.

In 2007 the school added a PhD program, 35 years after the public policy programs began. Faculty had sought it for years, Cook said.

“It was always a question of resources,” Cook said. During his first four years as director and chair, he wrote memos to university deans saying, “We desperately need more faculty members. Look at this huge crush of students we have. We are really scrambling to keep up and our ratios are so much higher than other departments.”

“I think they were routinely put into the ‘circular file.’”

Adding faculty to the public policy department was not a Duke priority at the time. In the 1980s, the university was focused on enhancing its reputation for scholarly excellence, an endeavor tied closely to the strength of PhD programs, which Sanford did not yet have. There was also less appreciation for a department that drew on multiple disciplines and emphasized the application of theory to practice.

Although the policy program had begun because of a push from the very top – Duke President Terry Sanford – “he was not an academic but a lawyer, a doer, a politician,” Cook said. “For him it was natural to think a university’s mission should include making a difference in the quality of life in the country, but that view was not widely shared. It was a pretty hostile environment, it should be said.”

Over time, attitudes changed -- so much that in 2008 when Sanford was in the process of becoming a school, Duke President Dick Brodhead referred to public policy as the “glue” that binds together many of Duke’s scholarly activities. Now, engaging with the public, media and policymakers -- putting knowledge and research “in the service of society” -- are written into the university’s strategic plan.

Supporting Sanford’s aspirations, Cook said, “always seemed to me to be the right answer, and eventually the university caught on.”

Cook is gratified he made commitments to Sanford, to Duke, and to a scholarly life; it was the right fit.

Featured Audio

Phil Cook: How Criminals Get Their Guns