DD will be sitting 11+ in September having just turned 10 the month before.

I understand that her DOB affects her scores but I don't know how!

Does it mean that she can get more wrong?

Depends on the school, but most schools standardised the scores.

However this doesn’t mean scores have marks ‘added to’ or ‘taken away’.

Children have their raw score compared to children born in the same month (for GL anyway, CEM are a bit more secretive about exactly what they do but something similar) then the different months are compared to see if there’s any significant differences.

If there’s no difference based on ages then there’s nothjng in the way of adjustment, if there is a diffrence based on age then scores are adjusted to suit. This way no one is advantaged or disadvantaged due to age.

I don't think that it is done on an individual school basis in Kent, I was under the impression that it was county wide.

Have a look at this, it's KCC's information and mentions standardising scores.

https://www.kent.gov.uk/education-and-c ... test#tab-5

_________________
Knowledge is knowing that a tomato is a fruit, wisdom is not putting it in a fruit salad !

It has absolutely NOTHING to do with the individual schools!

Sorry, I was generalising across the country, and hadn’t taken in it was just for Kent. (Hence my commentvabout GL and CEM).

Yes, elsewhere some schools run their own test - St Olave's does, and doesn't (or didn't) standardise for age.

In principle it would mean that your daughter will need a slightly lower raw score to achieve the same standardised score as someone who is born in September. I say in principle, because the standardisation works by looking at the standard deviation by month and so it is perfectly possible - although unlikely - that those born in August, e.g., score higher than those in May which would mean that the May-borns would need a lower raw score. In real terms, it is probably only a matter of a few marks but, it all depends on the cohort!

Also have a look at this with a response from Kent re the standardisation:

https://www.elevenplusexams.co.uk/forum/11plus/viewtopic.php?f=19&t=52403&start=30

A few years ago I investigated the age standardisation in the Kent test and came to the conclusion that there is insufficient leeway given to children almost a year younger than the September borns.

Unsurprisingly and depressingly the number of autumn borns in grammar schools far outstrips the number of summer borns. There is a much lower percentage of summer borns that take the test to start with. The age standardisation of course is only based on children that take the test to start with - and the difference between Sept borns and Aug borns taking the test is depressingly large.

There isn’t so much of a marked difference at the higher end it seems - anecdotally I know many summer borns in super selectives, it seems to be that the “normal” grammar schools are stuffed to the gunnels with autumn borns.

It means she will be a year older every August.. for the vast majority of schools it will make no difference at all

My experience of having a summer born child was that she simply was not mature enough to sit an 11+ exam at just 10 years old. I am not alluding to the exam itself but being put in a scary big hall with a whole load of other kids that she didn't know. She was not mature enough to cope with marking answers on a separate sheet or mature enough to cope with that sort of stress.
Summer born children have to cope with a lot. Whilst my DD holds her own very comfortably academically, she is still quite clearly immature in many ways in comparison to many in her class.