For research I am pursuing on the size of the ethnic Latvian population in the United States, I want to make sure my understanding of full-count IPUMS data is correct.
Prior to the 1930 census, Latvian (Lettish) speakers were grouped with Lithuanian speakers, meaning that from published census data we did not have a clear idea of how many persons reported Latvian as their mother tongue (MTONGUE).
However, the IPUMS full count data show a case count of 8,800 persons reporting Latvian as MTONGUE in 1910. As I understand it, IPUMS and Ancestry.com worked together on the full count. If even ball-park accurate, the number would suggest a much smaller Latvian-speaking population than those found in contemporary reports. With what degree of confidence can we say that 8,800 persons reported Latvian as their mother tongue in 1910?