As Symbiote explains above, units are just (volume * %ABV) expressed in a standard unit -- centiliters. It seems like a great system... it's like "standard drinks" in the US but actually printed on bottles. I imagine removing the need for people to do multiplication in order to figure out how much they are drinking is probably a good thing.

Units are centilitres, so why not just say centilitres?

If the intent is to communicate to the public, this is not an effective way to do it.

It's absolutely effective. Much of the public aren't as educated as we might like, and communication needs to be as simple as possible. Using units of measure will only serve to confuse, because it adds additional complexity in interpreting the advice.

"Units" reduce the complexity to a single number. For most drinks it will be 1, 2 or 3 units. Simple numbers, single digits.

General health advice will state that n units are the maximum recommended per week or day for men or for women. It's a single number to remember. Make sure the drinks you have total less than that maximum number, and you'll be following the recommendations.

The aim here isn't to be scientifically accurate. It's to reduce the problem to its essentials so that the message is clear and simple, and everyone in the entire population can understand it and follow it. By that measure, it's wildly successful.

> Using units of measure will only serve to confuse, because it adds additional complexity in interpreting the advice.

Units are an unit of measure. It's literally a different name for a centilitre.

> "Units" reduce the complexity to a single number. For most drinks it will be 1, 2 or 3 units. Simple numbers, single digits.

Centilitres reduce the complexity to a single number. For most drinks it would be 1, 2, or 3 centilitres. Simple numbers, single digits.

> General health advice will state that n units are the maximum recommended per week or day for men or for women. It's a single number to remember. Make sure the drinks you have total less than that maximum number, and you'll be following the recommendations.

General health advice will state that n centilitres are the maximum recommended per week or day for men or for women. It's a single number to remember. Make sure the drinks you have total less than that maximum number, and you'll be following the recommendations.

Its incredibly effective.

One shot is one unit.

One beer is 2-3 units.

One glass of wine is 2-3 units.

It is very simple maths. The kind you find hard to mess up when drinking.

It's incredibly ineffective, or people wouldn't be asking so many questions about it on this thread.

One shot is one centilitre.

One beer is 2-3 centilitres.

One glass of wine is 2-3 centilitres.

It's not maths at all, it's just communication. There's nothing "simpler" about "unit" than "centilitre", it's just less clear.

People asking questions are being obtuse and also clearly aren't in the UK where this legislation is aimed.

It would be like a continental European going to America and going, "What are all these MILES things? It's confusing!".

I'm an American, and miles are confusing.

A "unit" is a specific amount of alcohol though. Not very obtuse if you are familiar with it, and know that, for example, a pint of session ale is around a couple of units. The minimum price is applied per alcohol unit.

A 'unit' in Scotland/UK is 1cl of pure alcohol. So to get the number of 'units' of alcohol you multiply the the 'strength', in % ethanol by volum, by the volume of the container it is sold in. So a 1 liter bottle of vodka is 1l x 40% = 40 units and a bottle of wine in 0.75 x 13% = 9.75 units.