ACORN classification confusion

Universities don’t use ACORN for contextual offers. ACORN is a profiling developed for marketing and doesn’t demonstrate anything about education deprivation.
You need to check with them directly what criteria they use. POLAR, IMD and SIMD are the most common.

This is not true. An increasing number of universities do use ACORN for contextual offers, e.g. Manchester, Oxford, UCL and Imperial. There's an increasing view that it provides more accurate information on socio-economic deprivation than IMD, as it's more localised and granular. POLAR and TUNDRA measure rates of progression to higher education (as opposed to social-economic deprivation), so are different, but both are also used by universities. As has been said in this thread, universities all differ on what contextual offer criteria they use (postcode or otherwise), so it's still important to check their websites. (Some now have a checking tool where you can see if you're eligible or not.)

Why Acorn is rubbish - this is what it states for my postcode
Wealthy, car ownership at 3+ per household, high health and average salary of £60k+
In reality - it’s a council estate where over 50% of households have a disabled resident and it’s in the lowest decile for income, health and economic activity with only around 50% of households having access to a car.

The house in the photo does look lovely though! 🙈

It’s a 4 month old post. Things change.
Manchester and UCL yes they do use Acorn alongside polar. Oxford don’t make contextual offers (they consider contextual data but do not make lower offers) and Imperial use IMD and polar for both 2024 and 2025 entry.
I wouldn’t say it’s particularly increasing aside from in a handful of universities who find it more manageable for their A&P agreements to focus on the acorn marketing dataset than the more detailed (and difficult) IMD - particularly where they recruit from London where polar is a disadvantage due to the high progression to HE rates.