Robert 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 collapsed as an institution in the United States, 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. Mr. Fogel, a Chicago resident, spent much of his career at the University of Chicago and directed its Center for Population Economics.
Mr. 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.
Mr. Fogel drew on historical documents and then used modern computing systems to process the information.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, Mr. Fogel grew up in New York City during the 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.
Mr. Fogel's "Time on the Cross: The Economics of American Negro Slavery" (1974), co-written with economic historian Stanley 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 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.
Mr. Fogel and Mr. 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.
"The marketplace could not have ended slavery, because slavery was an efficient and profitable system," he told the University of Chicago Chronicle in 1993. "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. Mr. 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 Mr. 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.
Robert William Fogel was born July 1, 1926, in New York City.