Public fears that census data could be used for nefarious purposes are hardly baseless. In this extract from her new paperback, Timandra Harkness shows how mechanised data collection was used to target Jews in World War Two – and how one brave, early computer expert sabotaged it to save lives
In 1880, the US Census was struggling to turn all the data it collected on America’s growing population (50 million and rising) into information it could use, and announced a competition to find a better way to do the job. Former employee Herman Hollerith won the competition with his ingenious punch-card system. Recording the census data on punch-cards wasn’t so revolutionary: a human still had to make a hole in the right place on that household’s census card. The real revolution was automating the reading of the punched cards. Using Hollerith’s machine, an operator could process and sort 7,000 cards a day.
Hollerith established the Tabulating Machine Company in 1896 to provide what we’d now call data-processing services to the US Census Bureau and other customers, including several European governments. By 1924, he had merged it with other companies to form the Computing-Tabulating-Recording Company, and retired to keep Guernsey cattle. New company president Thomas J. Watson Sr changed the name to International Business Machines – IBM.
Punch-cards became the standard method of storing and transferring data. Processing them became faster and more accurate as electronic machines took over the laborious punching and sorting previously done by humans. By 1939, IBM had plants in England, France, Italy, the Philippines and Germany, and subsidiary companies all over the world. The company was close to having a worldwide monopoly on the major information-processing technology of its day.
In the IBM section of California’s Computer History Museum, a rousing chorus of ‘Onward, ever onward!’ rings out: IBM employees, literally singing from the company song sheet. In fact, there was a whole company song book, a generous system of rewards for successful salesmen, rules of conduct (no alcohol during business hours) and a company motto: ‘Think!’
The song is so catchy that for days afterwards I find myself humming, “Ever onward, IBM!” But one item in the IBM section of the museum brought me up short. All credit to museum sponsors IBM for acknowledging this part of the company’s history, I thought.
It’s a photograph of Thomas J. Watson Sr, in Berlin on 28 June 1937, taking tea with Adolf Hitler.
Dachau concentration camp. Photo: Bruna Santos/Unsplash
The role that IBM’s German subsidiary, Dehomag, played in the Third Reich is described in appalling detail in Edwin Black’s book, IBM and the Holocaust.
Dehomag was older than IBM. In 1910, German adding machine salesman Willy Heidinger licensed Hollerith’s technology and created Deutsche Hollerith-Maschinen Gesellschaft – Dehomag. Hollerith’s company got a share of Dehomag and royalty payments, a relationship that survived the First World War, but not Germany’s post-war hyper-inflation. In 1922, Watson did a deal that left IBM owning 90 per cent, with Heidinger still in charge on the ground.
In 1933, within months of Hitler coming to power in Germany, Dehomag had won a huge contract to run the census that would register all Germans, sorted by age, sex, occupation, religion and race. That census was only the beginning of a regime that would track everything in the expanding territory of the Third Reich via IBM’s punch-cards: buildings, raw materials, money, weapons, food, vehicles, horses, cows, railway rolling stock and, of course, human beings.
Many countries and US states passed eugenics laws in the early 20th century. Hundreds of thousands of people were sterilised without their consent. The first American state to pass a compulsory sterilisation law was Indiana in 1907, and the last American state to repeal its sterilisation law was Oregon in 1983. Denmark, Sweden, Norway, Finland and Iceland all had laws in effect until the 1970s. So, when Hitler passed the Law for the Prevention of Genetically Sick Offspring, in January 1934, he was not completely out of step with European or American government thinking. The compulsory sterilisation programme began with mental and physical disability or illness, and rapidly moved on to people displaying the wrong attitudes or ‘anti-social’ behaviour.
By the time Watson took tea with Hitler in 1937, it was very clear that Hitler’s Germany was a dictatorship pursuing a specific and brutal policy against Jewish people, and other ‘undesirable’ groups. On the same 1937 visit, Watson accepted Hitler’s medal, the Merit Cross of the German Eagle with Star, for ‘foreign nationals who have made themselves deserving of the German Reich’.
So central was IBM’s punch-card technology to the Reich that concentration camps had their own record offices, and sometimes their own Hollerith machines, tracking each person’s fate. Codes on the cards distinguished different classes of inmates – homosexuals, political prisoners, Jews, and so on – any work skills, and their eventual fate. Only those who were murdered immediately on arrival did not enter the system.
The Reich suddenly saw how utterly dependent it was on this all-pervading technology
In June 1940, after the Nazis had annexed Austria and invaded Czechoslovakia, Poland, Denmark, Norway, Holland and Belgium, Watson wrote to Hitler to return his medal. While this played well at home, it was the beginning of tense negotiations between IBM, Dehomag and the Nazi government. The Reich suddenly saw how utterly dependent it was on this all-pervading technology, and how much intimate knowledge IBM potentially had of almost everything the Reich was doing, or planned to do in future.
The ultimate outcome was satisfactory to Watson: American IBM retained majority ownership of Dehomag, but gave up detailed knowledge of its operations. This would later enable Watson to collect machinery and other assets in post-war Europe, while denying knowledge of the uses to which it had been put.
Meanwhile, IBM in America was indispensable to the US government: the Social Security system, armaments, personnel, transport and money, were all tracked and recorded via IBM’s ubiquitous punch cards.
The American census of 1940 also enabled the US government to identify Japanese Americans. They got around the law preventing release of individual details by showing the relatively few geographical areas where Japanese Americans lived, sometimes down to the city block. In 1942, in the aftermath of Pearl Harbor, that information was used to forcibly relocate and intern over 100,000 people in camps, where most of them stayed for several years.
In 1940, the Comptroller General of the French Army was an enthusiast for punch-card technology named René Carmille. He had visited Dehomag in the 1930s, and in 1934 he proposed a twelve-digit identity number to help with France’s mobilisation for the looming war. In the chaos of the German invasion of France, Carmille took control of as many punch-card machines as he could, of all brands, even ordering new ones. In 1941 he created the new Vichy Government’s National Statistics Service in Lyon.
René Carmille (1886-1945). Creative Commons licence.
Finally, Carmille could create a national identity system that would allocate each person a unique thirteen-digit personal identification number. Carmille proposed a national census, which would, among other things, identify all Jews with a hole punched in column 11. He also offered to process the specific ‘Jewish census’ completed in 1941 in both the Vichy-controlled south and the German-occupied north of the country.
After some bureaucratic wrangling, the transfer of 140,000 Jewish census forms to Carmille for tabulation began in 1942. The Reich hoped for an efficient deportation to the death camps like the one under way in Holland, where a national ID card, devised and enthusiastically implemented by demographer Jacobus Lentz, made it easy for the occupiers to pick out their targets, even from a population that actively resisted their efforts.
But Carmille’s processing of the Jewish census, and of the national census, was not as speedy or efficient as in other occupied countries. In fact, by the beginning of 1944 he still did not have the completed register of Jews that Adolf Eichmann wanted, to fulfil France’s quotas for deportation and murder. The Gestapo grew suspicious. In February 1944 Carmille was arrested, along with his office manager Raymond Jaouen. Carmille was tortured by the infamous Klaus Barbie, head of the Gestapo in Lyon, for two days without cease, but revealed nothing that could incriminate any of his fellow officers in the Resistance.
While the Reich hoped Carmille’s punch-card machines were readying a harvest of Jewish souls, he was, in reality, preparing information for Allied forces to launch a counter-attack, which began in North Africa in 1942. Local French forces joined American and Allied fighters in Algeria, helped by the information supplied by Carmille’s office. Using his position at the heart of national statistics, he also prepared false ID papers for many agents and fugitives, even getting equipment and examples to London so identity cards could be made for spies and Resistance fighters entering France.
While the Reich hoped Carmille’s punch-card machines were readying a harvest of Jewish souls, he was, in reality, preparing information for Allied forces to launch a counter-attack
What Carmille did not prepare, from either the national census or the paper records sent to him from the Jewish census, was a unified register to identify individuals for deportation and murder. Some say he even sabotaged the card-punching machines so they could never punch a hole in column 11. That register still did not exist when France was liberated in 1945.
Sadly, Carmille did not witness that liberation. Carmille and Jaouen were transported to Dachau concentration camp. Jaouen perished on the journey. Carmille died in January 1945, aged 59.
The punch-card systems provided by IBM epitomise how information technology made possible the mass society of the mid-20th century. Social security and health systems; employment and production by multinational corporations; mass warfare and organised mass murder – all depended on mechanised data collection and processing that reduced each living person to a number.
It is easier to go along with punching code F-6, ‘death by special treatment’, into a card than with consciously extinguishing the universe of a unique human life.
But it is also only possible to mount a war that defeats the Nazis with a detailed and up-to-date knowledge of the people, equipment and supplies you have on your side, where they are and where they are needed. As René Carmille showed us, technology can also be used to defend humanity against dehumanising regimes.
This is an adapted extract from Technology is Not The Problem by Timandra Harkness, published in paperback by HQ on 3 July 2025.
Timandra Harkness is a journalist, broadcaster, “lapsed comedian” and author of the books Big Data: Does Size Matter? (Bloomsbury Sigma) and Technology is Not the Problem (HQ). She is also a postgraduate research student in Philosophy at Birkbeck College, and a graduate fellow of the Royal Statistical Society.
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