Bio-banding. Is it the answer or just another challenge in RAE? In Player Development Project Magazine Issue #10, Cruyff Football and Ajax consultant Steve Lawrence gave some background to relative age effects, explaining why they occur and identifying the use of cut-off date rules as the causal culprit. Steve is at the forefront of research in this area, and in this follow-up article he explains the concept of bio banding and suggests how to solve the issue of relative age effects.

Concerns about relative age effects (RAE) tend to coalesce into two main areas, firstly to do with participation and secondly to do with talent identification and high performance development.

Participation in sport is almost universally encouraged for children. We know there are significant and diverse benefits, from social inclusion, to reducing obesity, to brain development and the promotion of long-term good health.

So my view of RAE in respect of participation is that it should not serve as a disincentive to participation, and by and large that means that age restriction rules should be seen by children as fair and that they should not be put off participating because they see themselves as not being good enough. That is what happens in an age restricted cohort where the youngest see themselves as lacking competence and are reluctant to participate and even drop out as a result.

In street football we see all ages, sizes and skills playing together – the tendency in a mixed age group is towards inclusion not exclusion – and teams tend to be chosen to make games competitive because that is where the fun lies.

“…imagine a structure where those who wanted to participate could participate” 

When children choose their own rules they don’t exclude but as soon as adults restrict a game with an age cut-off date rule some potential participants have to be excluded because the adults say so.

Now imagine a structure where those who wanted to participate could participate and where the adults who administrate football adopted a participation rule which was inclusive rather than exclusive.

The reasons for using a cut-off date are administrative. School teams and so on have to be organised in some way and a cut-off date rule reduces the workload of the already hard-pressed team coach or sport teacher. Administrative convenience wins out.

But let’s just think back to how children organise themselves in street football. Two team captains A & B. A picks first then B, then A again, then B again and so on until all participants are on a team. Those teams are selected on the basis of ability, size, age and friendship with a view to competing. It’s actually a sophisticated form of bio-banding and each team will tend to line up with equivalent aggregate BMI, average age and average skill levels.

If there are any significant distortions which threaten fairness or compromise safety, children will instinctively switch players around or divide the game into two, a younger game and an older game, all in the spirit of keeping it fun.

Whilst this might be a model based on natural human behaviour and fine for the informal setting of the street or the park, how can we adapt it to meet the needs of adult administration?

Adult administration is necessary for organised games within the context of school or league structures and adult administrators chose a cut-off date rule to do this. It was an idea which followed from the organisation of the school year and they were unaware of the RAE which would unfold over time and lead to extreme bias as competition became more intense.

We can also ask the question: is such a model appropriate for talent identification and development? I would argue that the model is inherently good at identifying talent – the selection procedure within the game actually does it. Early picks for sides tend to be those who will contribute most to the match outcome. Now imagine removing the early picks from the game. Does the competitiveness or the fun change? No, of course not, the character of the game will be different but other players emerge to fill the shoes of the departed and maybe some from the side-lines join in and the game goes on.

“…street to elite’ football pyramid wholeheartedly encompasses participation and provides a structure for talented individuals to progress up the hierarchy”

Our talent identification process has now selected a group of more able players and if we group them together with other such groups we will have added a layer to our pyramid of competition. By repeating the process we establish a hierarchy of competition where talented individuals will tend to rise through the layers to the top.

So, conceptually, our ‘street to elite’ football pyramid wholeheartedly encompasses participation and provides a structure for talented individuals to progress up the hierarchy to a level which is appropriate for their ability.

The thing it does not do is organise children into coherent groups to suit the administrators at school or in district and regional competition, and this is where it gets tricky because sticking children in year pools is very easy – and administrators do like an easy life.

So where might we find an alternative to cut-off date rules?

Ideas which have been discussed and in some cases piloted are quotas, parallel competitions and moving cut-off dates.

1. Quotas – quotas require the selection of teams to be made up with an even spectrum of birth months across a squad. On a quarterly basis this would mean 25% from Jan-Mar, 25% from Apr-Jun and so on. Whilst the present annual system is actually a quota system administrators are universally hostile at the mention of the word.

2. Parallel competitions have been tried and Belgium, for example, has experimented with parallel late-born squads in some international youth teams. In the Netherlands a group of amateur youth football clubs around Amsterdam and Utrecht is experimenting with a special parallel competition for teams entirely consisting of players born in the second half of the year. The competition is also devised for the finals stages to involve competition with the slightly younger pro-club youth teams (who have mostly early-born players).

3. Moving cut-off dates have been contemplated by a number of associations but have never been trialled. They fall into two categories: firstly the moving of the cut-off date by quarter year on year and in a four-year cycle. For example January this year, April next year followed by July and then October. In that way youth players would have the opportunity to be the oldest every four years. A variation of this is to have a totally random cut-off date probably chosen at least a year in advance to allow preparation to meet the requirement.

The difficulty with all of these proposals is administration: checking eligibility, setting competition rules, preparation in advance and meeting the criteria when the selection pool is small.

There is also another aspect to these various alternatives, which is that there is no obvious competitive advantage to implementation – and it’s my view that the driver for change will be competitive advantage.

Which is why the recent experiment at Southampton FC is so interesting. Southampton, along with Reading, Norwich City and West Bromwich Albion, recently used a bio-banding rule to establish competing cohorts. The driver behind this is talent identification. These clubs want to know if there are players whose ability can be observed to be different in different conditions.

The cohort was restricted to 12–14 year olds and the bio-bands were established using projected full-grown height, which is done by using age/height charts.

By all accounts the trial was very successful but full details have not yet been released by the Premier League, the monitoring organisation. You can read the results here.

If you refer back to our ‘street to elite’ model I think you can imagine that the ‘bio-banding’ model makes a very comfortable administrative partner at the ‘elite’ end of the hierarchy but not at the ‘street’ end of things where height charts and/or BMI calculations aren’t too easy.

The view I came to several years ago brainstorming this with colleagues, Ruben Jongkind and Florian Kugler, engaged in developing the Cruyff Plan at Ajax, is both simple and elegant and it encompasses ‘street to elite’ and ‘bio-banding’. It is simply to establish competition between two teams on an equivalent ‘average team age’ basis.

Not only is an ‘average team age’ a pretty good proxy for the ‘bio-band’, correlating closely with it, but it is much easier to calculate and administrate. It acknowledges the difficulty that Musch and Grondin (2001) identified in using anything other than a chronological age rule but at the same time encompasses the concept of bio-banding.

Dates of birth are already a recognised core piece of data for youth team organisation, and entering player names and birthdates into a simple iPhone or mobile app allows an average team age read-out instantaneously.

“I don’t imagine teams lining up with a very wide range of ages – it wouldn’t be sensible for 8 year olds to be lining up with 15 year olds for example”

In terms of a formal rule substitution an example would be:

‘Players are eligible to play in the competition if they were born on or after 1 January 2001.’

To be replaced by:

‘Any participating squad shall consist of 18 players whose average age on the first day of the competition shall be no more than 13.0 years.’

Now I don’t imagine teams lining up with a very wide range of ages – it wouldn’t be sensible for 8 year olds to be lining up with 15 year olds for example. I would argue, however, that it is desirable and appropriate to have a spectrum of age which may be different at different times on the age continuum, perhaps a 2 year restriction at younger ages of 6–12 perhaps rising to a 4 year spectrum at 17-21.

Thus a rider to the average team age rule would be something like: ‘the oldest player in the squad will be no more than 2 years older than the youngest player in the squad’. This rule is common in UEFA competition handbooks already.

So there we have it, a ‘street to elite’ pyramid of competition based on a universal ‘average team age’ bio-banding rule.

There is one last benefit which flows from this idea, and I believe that because it brings competitive advantage it will be the driver. And it’s this:

Imagine a younger but very skilful player entering such a pyramid. That younger, more skilful player will be a big advantage to any team because he or she brings the average age down whilst maintaining competitiveness. There is therefore a natural process of talent rising up the age groups to a natural skill level.

This creates the very real prospect of a system which encourages ‘talent emergence’ rather than depending on ‘talent identification’, and that has to be more efficient. Those who are first with this will be the early beneficiaries and that’s what will drive it.

I will be giving a presentation on ‘Relative Age Effects and the potential for Average Team Age Rules’ as part of the NextGen Talks Series which takes place in Amsterdam alongside the NextGen Series U19 Tournament, 14–16 May 2016. AFC Ajax, Tottenham Hotspur, PSV Eindhoven, Ajax Cape Town and Galatasaray are participants.

1 Barnsley, R. H., & Thompson, A. H. (1988). Birthdate and success in minor hockey: The key to the NHL. Canadian Journal of Behavioral Science, 20, 167–176.
2 Musch, J., & Grondin, S. (2001). Unequal competition as an impediment to personal development: A review of the relative age effect in sport. Developmental Review, 21, 147–167.


Cover Image: Kids play football at night. Photo: flickr/grotos

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