Robert W. Fogel drew on historical documents such as medical records, census data and pension documentation. One of his most controversial books disputed longheld assumptions about why slavery collapsed in the United States. (University of Chicago via Bloomberg)

Robert W. Fogel, a Nobel Prize-winning economic historian who used empirical data in innovative and iconoclastic ways, most notably to dispute long-held assumptions about why slavery in the United States collapsed as an institution, died June 11 at a rehabilitation facility in Oak Lawn, Ill. He was 86.

The cause was pneumonia, said his daughter-in-law Suzanne Fogel. Dr. Fogel, a Chicago resident, spent much of his career at the University of Chicago and directed its Center for Population Economics.

Dr. Fogel shared the 1993 Nobel Prize for Economic Sciences with Douglass North, then of Washington University in St. Louis. Both winners were on the 1960s vanguard of a field known as cliometrics, which merges economic theory with statistical analysis of hard numbers raked from the past; Clio is the muse of history in Greek mythology.

Dr. Fogel drew on historical documents such as medical records, census data and pension documentation, and then used modern computing systems to process the information. The Nobel citation credited him with “having renewed research in economic history by applying economic theory and quantitative methods in order to explain economic and institutional change.”

“Fogel was one of the intellectual pioneers and certainly the most visible member of a generation of economic historians who transformed the discipline from what had been narrative history into history informed by economic theory and statistical methods,” said Barry Eichengreen, an economics and political science professor at the University of California at Berkeley.

The son of Russian immigrants, Dr. Fogel grew up in New York during the Great Depression and became a Communist Party activist while an undergraduate at Cornell University in the 1940s. He eventually left the party, but a radical streak persisted in his professional life.

Innovation, controversy

Dr. Fogel studied history before turning to economics in the 1950s, and his doctoral thesis at Johns Hopkins University informed his first major work, “Railroads and American Economic Growth” (1964). The book was a riposte to railroad historians and other economists such as Joseph Schumpeter and Walt W. Rostow who trumpeted the vital role of railroads in U.S. economic and territorial expansion during the 19th century.

The book argued that in the absence of railroads, other forms of transportation like canals and horse-drawn wagons simply would have filled the gap and that the gross domestic product would most likely have suffered by only a few percentage points.

“Railroads and American Economic Growth” used what became a hallmark of Dr. Fogel’s technique — counterfactual historiography, or the building of a hypothetical alternative and then comparing it with the actual history.

“Few books on the subject of economic history have made such an impression as Fogel’s,” the Royal Swedish Academy of Sciences noted when Dr. Fogel received the Nobel. “His use of counterfactual arguments and cost-benefit analysis made him an innovator of economic historical methodology. Fogel’s painstaking criticism of his sources, and his use of the most varying kinds of historical material, made it difficult for his critics to argue against him on purely empirical grounds.”

If the railroad book boldly announced the presence of an idiosyncratic thinker, Dr. Fogel’s next major work would cement his reputation as an intellectual bomb thrower.

“Time on the Cross: The Economics of American Negro Slavery” (1974), co-written with economic historian Stanley L. Engerman, postulated that slavery was a thriving institution on the eve of the Civil War. The authors challenged a widely held view that slavery as an economic institution was in decline and even on the precipice of collapse when the war began in 1861.

He initially began the project to explore how less-efficient slave labor was compared with wage labor. “A lot of us, including me, believed that a system as evil as slavery could not have been profitable,” he told the Cornell alumni magazine in 2008.

A quick calculation, based on census data, showed the opposite. So he did more in-depth research, which relied on historical data up to 1860 about the prices of slaves and cotton, and food consumption by slaves and the larger population, among other information.

“At various points, we were so stunned by the results of what the other was working on that Stan and I were each prepared to accuse the other of finally having succumbed to racism,” he told the Cornell publication.

Dr. Fogel and Engerman concluded that many slaves, considered economic assets by their owners, were fed far better and worked less than some free, often exploited industrial workers in the North. They also asserted that some plantations were far more efficient than their counterparts in the North, and that the practice of slavery would have kept going if not for the Civil War.

“Our conclusion was that slavery was ended not because it was morally repugnant,” he told the University of Chicago Chronicle in 1993. “The marketplace could not have ended slavery, because slavery was an efficient and profitable system. Slavery ended only through political intervention based on the evolving American ethic against slavery.”

Predictably, “Time on the Cross” ignited intense criticism from civil rights groups and reviewers who charged the authors with an ugly form of revisionism. Dr. Fogel’s most vociferous critics charged him with racism, despite the fact that he was married to an African American.

The book won the prestigious Bancroft Prize and continued to draw controversy over the decades. The fierce reaction prompted Dr. Fogel to write a second book, “Without Consent or Contract: The Rise and Fall of American Slavery” (1989) to defend his work and include a moral censure of slavery.

Research on aging

Dr. Fogel’s most recent work — spanning several decades — helped open a new branch of historical inquiry by delving into the economics of aging, namely how economic and social conditions have affected the human body.

He was a co-author of “The Changing Body: Health, Nutrition, and Human Development in the Western World Since 1700” (2011), which explored the way improvements in technology, food production and public health have hastened human evolution in the last century in height, weight and longevity. He called it “‘technophysio evolution.”

“The rate of technological and human physiological change in the 20th century has been remarkable,” Dr. Fogel told the New York Times. “Beyond that, a synergy between the improved technology and physiology is more than the simple addition of the two.”

To reach his findings, he directed a team that plumbed raw data on health records around the world, as well as information about caloric intake of individuals over the millennia. The work was said to have potentially great consequences on public health and agricultural policies worldwide.

Robert William Fogel was born July 1, 1926, in New York. His parents had arrived penniless just a few years earlier but became ardent capitalists and eventually started a meat wholesale business.

He attributed his youthful interest in Communism to an older brother he admired and who seemed to be shaped by the Depression. No matter the question, the brother replied, “The answers to all that are in Marx.”

“I didn’t become a radical through my own experience of how terrible capitalism was — it was purely intellectual,” he told the Cornell publication. “I was a rich boy, the son of rich parents. And I believed that Marxism was the science of society and Marxists were the social scientists of the time.”

At Cornell, he majored in history, and after graduation in 1948, he worked in Harlem with American Youth for Democracy. There, he met his future wife, Enid Morgan, and as a mixed-race couple in the 1950s they struggled at times to find apartments to live in and restaurants that would serve them.

Enid Fogel became associate dean of students at the University of Chicago’s graduate business school, and Dr. Fogel once credited her with helping “boost my self-confidence when my unorthodox findings provoked controversy and criticism.”

She died in 2007 after 59 years of marriage. Survivors include two sons, Michael and Steven; five grandchildren; and two great-grandchildren.

Dr. Fogel reportedly quit the Communist Party in 1956 and charted an academic career that began when he enrolled at Columbia University for a master’s degree in economics. He graduated in 1960 and then received a doctorate in economic history from Johns Hopkins in 1963.

Engerman, now an economics professor at the University of Rochester, told the Cornell magazine that his former colleague “would always push at the evidence as hard as he could to see what arguments could be made. He never accepts the first answer, or the easy one.”