Starting next Monday, Aug. 19, listers will begin verifying the remaining 35% of addresses that need double-checking, using maps and a list of known addresses on a laptop. Mostly, they will be checking to see whether a basement was turned into an apartment, new housing was built, someone is living in a trailer on a property, or some other new or unconventional living arrangement exists, especially in areas that have seen a lot of growth. (The Census Bureau is alerting local police departments about the address operation.)