I am often asked whether an address is "deliverable", and not everybody is happy with my usual response that it depends on the mood of the postal staff on duty that day.
The point is that "deliverability" is unmeasurable, unscientific and has little basis in reality. Address validation software will often give a figure for the number of deliverable addresses within a file, such as 80%, but don't be fooled - this does not mean that, if you send a letter to each address within that file, 80% will get there and 20% will not. These numbers have been created to give some sort of feedback to the user, and to make files comparable with each other when run through the same software processes.
So how come there's no way to measure deliverability?
You could look at a country like The Netherlands, with its neat address system, and boldly state that a deliverable address is one where the postal code and the building number are present. Mind you, if either contain a typo, the mail may be deliverable, but not to the desired recipient. Equally, whilst TNT Post is happy with that much information, because it will get them to a letter box, to make a mailpiece deliverable to a person, more information is required - a sub-building indicator (as many addresses may share the same house number/postal code), a name, department and so on.
So, I've got all that. So the address is deliverable. Right?
A mailpiece containing my correct postal code and house number took 6 months to reach me. Not because the information was wrong, but because a second, stray, postal code had wormed its way into the address block, sending the mailpiece around the system ad infinitum. It was only when a particularly awake postal worker saw and crossed through the stray code that the mailpiece could get sent on its (correct) way.
But not having a full address, or even any address, does not make a mailpiece undeliverable! I remember the TV program That's Life! on the BBC successfully receiving mail sent with just a drawing of a prominent set of teeth on the front - an allusion to Esther Rantzen's somewhat toothy smile.
This Christmas a card was sent with this address on it:
Mr & Mrs T Burlingham?
Near the golf course in Thetford,
Trevor is a photographer. This might help
It did help. This undeliverable address took just 2 days to arrive. But this isn't just a British thing. How about one of my favourites:
Vukasin 6 years and Jelisaveta 3 years
I don't know the family name
Their father is big, he drives a Citroën Belingo.
He works on the little trains for tourists.
Postman: Please find them!
And he did!