Ages on the 1939 census

[Jill Eaton]

His death certificate gives his official date of birth - 31st August. I wonder when he actually celebrated his birthday!

[Mark1973]

I've found a few of my ancestors already where the birth day and month is correct but a year out.

[LizzieL]

I've found a few of my ancestors already where the birth day and month is correct but a year out.

I have too. I have mentioned this on earlier threads or maybe earlier on this thread. Even my grandfather and his identical twin brother. Grandad was a year wrong, but great uncle Bertie got it right. I was going back through them to check if there was a pattern.
I have a theory that people then didn't so much keep a record (in their heads) of their actual date of birth, but their birthday (day and month) and their age. So if they were asked dob and they just subtracted age from current year, they would be a year out (one year greater) if they had not yet had their birthday in the current year.
Now to see if my theory fits my rellies

[coombs]

Yes I have one rellie who gave 31 Dec 1864 in the 1939 register but it was 31 Dec 1863. Her parents were celebrating her first birthday on 31 Dec 1864. Some may have not kept an account of their actual year of birth but the day and month, and their current age as said, but they may not have known exactly how old they were. Today we seem to need our DOB to open an envelope. 

[LizzieL]

A bit of an aside, but related to dob. I went for a hospital appt yesterday. I was asked my dob by the computerised check in system at the outpatients entrance, asked it again by the receptionist when I got to the clinic, and by the consultant who was doing my treatment. Sometimes it's four times, this time the nurse who did the preliminary tests forgot.