In her testimony written in the immediate aftermath of the war, Suzanne Birnbaum, stunned by the pace at which the Jews of Hungary had been decimated at Auschwitz, wrote that 600,000 were murdered in July and August of 1944. The reality was somewhat less – we know now that the number of Hungarian Jews killed in this period was around 435,000. Nevertheless, Annette Wieviorka, in her study of testimonies of the immediate post-war period – of which there are a surprisingly large number – notes in response to this error that it ‘makes no difference to the insane scale of the massacre’.

But discrepancies of this sort do exercise historians, and rightly so, since they aim to compile the most accurate body of information possible. A well-known example of this sort of error is recorded by Dori Laub. At a conference on Holocaust education, a survivor's testimony was shown during which the narrator described how, during the Sonderkommandouprising at Auschwitz, she had seen the four chimneys of the crematoria blown up. The historians objected:

But as Jean-François Lyotard has shown, it is precisely because the factual record will remain incomplete, a result of the nature of the events themselves as well as the loss of documents, that Holocaust negationists are able to ply their trade. When historians argue over the number of people killed in death camps, for example, the negationists claim that nothing relating to the Holocaust can be ascertained. Turning the assumptions of historians on their heads, Lyotard argues that ‘the “perfect crime” does not consist in killing the victim or the witnesses…but rather in obtaining the silence of the witnesses, the deafness of the judges, and the inconsistency (insanity) of the testimony’.