In 1920 they used an enumerator, some one who physically went from door to door writing every thing down.
There is no question on the 1920 census that asks, "How long you have lived at this address?" If you moved in that day, well...
What is interesting is that the wife's first name is blank. This information matches all the other census records, regarding state of birth, parents country of birth, etc.
As is typical of many people in the firearms industry during this period Emil is living in a rooming house. I tracked Lefever employees over several years.
Almost to a man, if they were living in a rooming house, they moved every year.
The 1160157 patent gives a residence of Ithaca.
http://www.google.com/patents?id=HN8ZAAAAEBAJ&printsec=abstract&zoom=4&dq=1160157Pete
