Faded ink. Inconsistencies. Fires. The deadliest conflict in American history, the Civil War, also had some of its worst-kept records, making the true number of casualties seem forever elusive.
For decades, historians have cobbled together clues. But thanks to a newly released set of census records spanning three decades, researchers have landed on a firmer estimate of lives lost: 698,000.
The analysis, published this week in The Proceedings of the National Academy of Sciences, also suggested that the Confederate states fared much worse than the Union, with a mortality rate more than twice as high. The granular nature of the census data means that researchers who build upon the work will be able to better understand the long-term impact of the war in the hardest-hit regions.
Caroline Janney, a history professor at the University of Virginia who was not involved in the research, said that she was intrigued by the census-based methodology and excited that the state-by-state data is likely to have other rich information, such as migration patterns among the newly freed population.
But she warned against interpreting modern social and political dynamics too readily through the lens of the Confederate death toll.
“There’s a reason that it’s still with us, there’s a reason that the memory still lingers,” she said. “Those deaths very much did shape their respective societies, but in a far more complicated and nuanced way than sheer numbers can represent.”
An Elusive Count
Jeffrey Jensen, a political science researcher at N.Y.U. Abu Dhabi who is one of the authors of the new analysis, wanted to better understand the social and economic consequences of the Civil War. He decided to team up with researchers who study the legacies of political violence abroad.
Together, they sought to examine how such trauma had been memorialized in the United States. The team thought it would start by looking at the loss in sheer numbers. The problem was that the data set didn’t seem to exist.
“I study Southern political institutions, and I was as surprised as anyone,” said Dr. Jensen, who assumed the United States would have had a detailed account of the death toll. But the researchers found that the record-keeping in the Confederate Army began to erode as the war neared its end, and what did exist was burned in Richmond, Va., soon after.
Most historians, he said, had simply taken longstanding military estimates of fallen Union Army soldiers and simply applied the same share to the Confederate Army, and then added the two to get a count of 618,000 lives lost.
Then just over a decade ago, a demographic historian, J. David Hacker, developed a new method of calculating the loss: using census data to compare U.S. death counts in wartime versus peacetime. (His estimate: about 750,000.)
But Dr. Hacker’s calculation used a 1 percent sample of individuals from each of the 1850 to 1880 censuses, which meant the accuracy could be threatened by what statisticians call a sampling error. It also could not account for people moving between states.
New Opportunities
When the full set of individual census returns from 1850 to 1880 became available, Dr. Jensen and his colleagues dove in. They used a so-called sex differential method, separating the number of military-age white men born in the United States — since women did not join combat — and then compared 1860 (the year before the war started) with 1870 data (five years after it ended). They found a massive drop-off in the men: 496,332 fewer. After adjusting for soldiers who had not been counted in the censuses — Black men and men born outside the United States — using previous historians’ estimates, they arrived at a final estimate of 698,000 deaths in the war.
The census-comparison tactic alone, however, would not have worked for discerning the number of lives lost from either side, let alone from specific states, since many people who survived the war relocated at some point during the decade. A Union Army soldier who lived in a Northern state in 1860 but moved to a Southern state by 1870, for example, would wrongly add a Union Army death and subtract from the Confederate Army casualties.
To account for this blind spot, the researchers also had access to a sample of census records linked across multiple years, which allowed them to track the respondents over time and across state lines. (The same methods could be applied at a county level, they said, allowing scholars to take a more localized look at the war’s impact over time.)
By comparing census data that adjusts for migration across state lines, they were able to separate Northern and Southern deaths. The researchers found that Southern states had an excess mortality rate of 13.1 percent for white men born in the United States, more than twice the Northern rate of 4.9 percent. The study analyzed eight of the Confederate states and 13 Northern states. At least 10 percent of military-age white men were killed in seven Confederate states; the same was true in just one of the Northern states.
The worst-hit state was Louisiana, where the excess mortality rate among those men was 19 percent, with South Carolina and Georgia close behind.
Next Steps
Dr. Hacker, who carried out the original census-based estimate years ago, is now the principal investigator of the newly available census data sets used in the study. He said that he was pleased with the new analysis and that he was “looking forward to more research based on the new full count.”
Dr. Jensen and his colleagues are already taking their analysis further, examining how much of the loss in the Confederate Army was among soldiers who were not slave owners, for example. They ultimately plan to study the long-term effects, including the economic and social dynamics of the generations that followed.
“The South was an incredibly violent place after this,” he said. “I think a lot of people probably don’t want to hear it, but this mortality rate — the trauma is just unbelievable.”
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