Götz Aly and Karl Heinz Roth show in their book that the German Nazi system would not have worked without counting people, identification, classification, separation and elimination. It is a detailed historical account on technical details of coding and storing information about the population, the census of 1933 and 1939, the infamy of telling people that their data of Jewish ancestry in a separate questionnaire would be treated anonymously (p 93). The 1939 census required a “supplemental card” in addition to the household card (p 32)
This card developed by security service, police as well as statistical office was used by the authorities to ask for individual descend (“Was one of you grandparent Jew?”) as well as for the education in commission of the military services. The card should be given back in a separate, closed envelope. The envelope – together with the official affirmation – should delude potential victims and let them believe by the fictitious anonymity to make absolutely true information which was indeed facilitated and guaranteed.
The supplemental cards were then used to build the “Reichskartei der Juden und jüdischen Mischlingen” – the basis of the Holocaust. The Holocaust started with a knitting needle – the tool to lift the punched supplemental cards.
As mentioned earlier, I think there is a particular obligation with population based studies in Germany where it took 40 years to build epidemiology from scratch again. This is a must-read book for every epidemiologist.
A few hours before being executed, Eichmann was asked by Mr. Ofer, the director of the prison (in my translation)
“What should the Jews have done? How could they have resisted according to your opinion? Eichmann: Disappear, disappear. Our most sensitive point, that they would disappear before being registered and concentrated. Our command units were too weak and even when the police of the respective countries supported us with all their strength, [the Jewish] had a at least a chance of 50 : 50. A mass escape would have been a disaster for us.