Knowing and using birth date information can ensure that, whatever age a child is, sensible assumptions can be made about progress, ability and development. It can help to understand both those who seem to high flyers and those who appear to struggle. If age is not considered, wrong and unhelpful conclusions are highly likely to be made about what children can do.
In England, we group children into a school year cohort based on their date of birth. Unlike a calendar year, the school year starts on September 1 and continues through to August 31. There is no particular reason for continuing to do this other than historical precident – and other countries have quite different school years, often running from January 1 to December 31 – but it is what it is, and we have work with the implications of the arbitrary cut offs.
Whilst children are supposed to start school when they are five years old, in practice this has become the September before their 5th birthday. For some children, this means starting school when they are 364 days away from their 5th Birthday, and, on average, children start six months earlier than they should. Campaigns highlighting this anomaly are underway, but there seems to be little official desire to enforce current legislation, and some groups are actively encouraging assessments of children at earlier and earlier stages of their lives.
The difference in age within a cohort is significant for most of children’s time in education; in some important ways it is always significant and it can have a huge influence on a children’s sense of their own abilities when compared to their peers. It’s worth looking closely at the difference birthdate can make to a child in school.
September-borns just got lucky
In reception, the youngest child in a cohort will start at 48 months old, and the oldest will be 59 months old. By the time of the Year 1 phonics check in May of Year 1, the youngest will be 69 months and the oldest 80 months. The oldest have had around one seventh more experience as a result.
If you consider that most children become confident talkers at around 30 months of age (as a rough figure), and that thought develops with language, that means that when they start reception the September-borns have actually being developing their intellect for 29 months compared to just 18 months for the youngest. That’s more than 50% more time than their August-born class mates.
The difference is still significant when children sit SATs in Year 6, when the youngest are 129 months old compared to the 140 months the September-borns have under their belts. Remove the first 30 months in the pre-language phase, and the difference is 99 months to 110 months, a huge 11% more time to grow, learn and develop.
Here is a graph of mean standardised average point score at Key Stage 1 and Key Stage 2 by birth date and cohort, based on analysis undertaken by the Institute of Fiscal Matters:
Being older is a huge advantage in non-academic areas
Malcolm Gladwell explored this in his book Outliers, where he looked at research into the ages of NHL Ice Hockey Players. Players are grouped by year based on their birthdate, with a hockey year beginning in January and ending in December. The physically bigger children born in the first three months of the year are consistently selected for higher level coaching and game play, and by the time players enter the NHL, the difference in the quarter in which you were born is staggering.
Of course, this is not written in stone, and children can gain advantage in other ways; the children of sportspeople are often good at sport, musicians tend to have musical children and so on. Parents who are aware of the effect of age can do quite a bit to mitigate the effects of birthdate, but the simple fact that some children are considerably older or younger than their peers has a huge effect.
The more able are often simply the older children
A few years into my teaching career, I was asked to teach a Year 6 class. With the test-based requirements of the last year of primary hanging over me, I set about assessing the children’s ability to shine under test conditions. And, because I was young and keen, I looked for patterns in the data I gathered.
The thing which became obvious as I looked closely at the class I was teaching was that the oldest children were invariably also the most able, whichever subject I looked at. Likewise, the ‘less able’ tended to be the younger children in the cohort. I taught in a single form entry school, and all 30 children were in my class, so I could see the effect of age clearly.
Since then, I’ve always started the year by seating children in age order. After a few weeks, I put everyone into ability groups, as demanded by the current view of primary education. I usually have to move a few children around, but not by very much. But it reminds me that, just because a given child can do more than another, it doesn’t necessarily make them more able. It often means they are older, or that their parents know what will help their child in school.
March 2nd is important
The middle of the school year is on the second day of March, with 182 possible birthdates before and after this date. For a given school cohort, it is very illuminating to look at the spread of ages within a class around this date.
I recommend looking at two different measures:
1) Know your seasonal groupings
Group the children into Autumn, Spring and Summer, with a four month spread in each group. Look at this regularly to keep the different groups familiar.
2) Know the mean age difference between different groups within your class
I define the 'mean age difference' as being the mean difference between a cohort and March 2nd, the middle of the school year.
Compare the data for boys and girls, and for maths, reading and writing groups, using a simple spreadsheet to find differences between birthdate and 2nd March and then calculating the mean age difference.
It’s often illuminating to see how age affects sporting and creative ability, too. Some of the younger children in a cohort are often neglected because they have had less time to practice.
I always look for those children who are not where you might expect them to be, either because they have made significantly more or less progress than their peers.
There is a reasonable body of research on the effect of age on children’s progress in school, and I recommend the Institute of Fiscal Matters report ‘When you are born matters: the impact of date of birth on educational outcomes in England’ for further reading.
This is the kind of data which we should use in school, free from bias and providing useful insight into how best to help children in the school system.
August 2014 update: I have added a sample spreadsheet here following a request by TFScientist below. It should be self explanatory, but feel free to ask questions in the comments below.