Based on the solution to determine age x definition: "...x = age next bday on Jan 1 in the calendar year of census = age nearest 1 July in calendar year of census = age nearest at the date of census. Then I thought, the average age (at start) on Jan 1 is between (x-1, x) therefore x-1/2, so the age at July 1 would be x. Is this right, or is there something I need to be aware about, for instance, if this is a calendar year, then all lives will change age label together, so there is no need to take the mid point of the ages at start.
