If you thought you knew how many died in the U.S. Civil War, you may be wrong, according to this morning’s New York Times. David Hacker of Binghamton University has offered new estimates in the December 2011 issue of Civil War History of the number of men killed in the Civil War (not women, see the article for why) that increase the total by about 20%. [NB: if you have access to Project Muse, you can read the Civil War History piece here.]
Hacker made the estimates by blending traditional methods of statistical estimation with new tools available digitally:
Enter Dr. Hacker, a specialist in 19th-century demographics, who was accustomed to using a system called the two-census method to calculate mortality. That method compares the number of 20-to-30-year-olds in one census with the number of 30-to-40-year-olds in the next census, 10 years later. The difference in the two figures is the number of people who died in that age group.
Pretty simple — but, Dr. Hacker soon realized, too simple for counting Civil War dead. Published census data from the era did not differentiate between native-born Americans and immigrants; about 500,000 foreign-born soldiers served in the Union Army alone.
“If you have a lot of immigrants age 20 moving in during one decade, it looks like negative mortality 10 years later,” Dr. Hacker said. While the Census Bureau in 1860 asked people their birthplace, the information never made it into the printed report.
As for Livermore’s assumption that deaths from disease could be correlated with battlefield deaths, Dr. Hacker found that wanting too. The Union had better medical care, food and shelter, especially in the war’s final years, suggesting that Southern losses to disease were probably much higher. Also, research has shown that soldiers from rural areas were more susceptible to disease and died at a higher rate than city dwellers. The Confederate Army had a higher percentage of farm boys.
Dr. Hacker said he realized in 2010 that a rigorous recalculation could finally be made if he used newly available detailed census data presented on the Internet by the Minnesota Population Center at the University of Minnesota.
The center’s Integrated Public Use Microdata Series had put representative samples of in-depth, sortable information for individuals counted in 19th-century censuses. This meant that by sorting by place of birth, Dr. Hacker could count only the native-born.
Hacker then revised the data to control for the normal mortality rate and other factors, and acknowledged problems with estimating deaths for women (both white and black) and for black men. The new counts overturn data that historians have relied on for over a century. In a blog post last fall, Hacker answered the question of why the revised higher count matters:
So what? Above a certain count, do the numbers even matter? Well, yes. The difference between the two estimates is large enough to change the way we look at the war. The new estimate suggests that more men died as a result of the Civil War than from all other American wars combined. Approximately 1 in 10 white men of military age in 1860 died from the conflict, a substantial increase from the 1 in 13 implied by the traditional estimate. The death toll is also one of our most important measures of the war’s social and economic costs. A higher death toll, for example, implies that more women were widowed and more children were orphaned as a result of the war than has long been suspected.
The techniques that Prof. Hacker employed are fascinating, and point to some of the possibilities in thinking about newly digitized data sources. My question, however, is why—after publishing Hacker’s post on the Disunion blog last September, and with his journal article in print for four months—the Times waited to publish this piece until just now.