Jody - the censuses give the relationship to the head of house.It might say "wife" or "daughter" or "servant"So if Joe Murphy is head of the household, and his occupation is farmer, you may see below someone with a different surname whose occupation is listed as farm laborer. That person likely lives on the premises. You may also see a son listed with an occupation as farm laborer. You might find a son listed as a clerk or a daughter as a shop girl.In those cases the children probably have jobs which may not be in the same occupation as their parents, but are living with the parents. The census instructed inhabitants to put down anyone in the house the night of the census.My father was 3 at the time of the 1911 census and is listed as a visitor, and his relationship as nephew at his aunts' and uncle's house.