Upper Silesia was formally assigned to Poland by the League of Nations after the census was conducted elsewhere.

Meanwhile, the conditions in eastern Galicia were still unstable and chaotic, and the census data had to be adjusted after the fact, wrote Joseph Marcus, thus leading to more questions than answers.

Also, specific areas of considerable size lacked complete returns due to absence of war refugees.

[2] Entire categories considered essential today were absent from the questionnaires, subject to historic interpretation at any given time.

The categories listed in the census included verbatim: Narodowość: polska (polonais), rusińska (ruthènes), żydowska (juifs), białoruska (biėlorusses), niemiecka (allemands), litewska (lithuaniens), rosyjska (russes), tutejsza (indigène), czeska (tchèques), inna (autre), niewiadoma (inconnue).