Thank you very much to Tzavosky for this wonderful contribution that analyses the birth dates of the Craven Week players and the current Springboks:
It has been known for some time and supported by several studies in different sporting codes that an athlete’s date of birth can determine their success at an elite level in that code. Studies have been done for soccer, Australian league and Canadian Ice hockey that I’m aware of.
The general conclusion is that a kid born in the first 3 months of a sporting code’s season, but definitely in the first 6 months, has a disproportionate chance of success, based on the fact that they’re at a more advanced level of physical development than those born later in the season.
They will therefore be preferentially selected for coaching and conditioning, which will further their development. Those born later in the year on the other hand are psychologically disadvantaged and may give up – almost a type of self-fulfilling prophecy.
With this in mind, I went to SARU’s data base and checked the birth dates of all the players for the upcoming Craven week (Namibia excluded, as there is no profile information on their players). As can be seen below (number of players per birth month for each team), this general rule of thumb holds true. Its overwhelmingly true for most teams, but strangely enough does not apply for Boland, Border Country Districts and Griquas Country Districts.
I went one step further and checked the birth dates of the 28 Springboks that took the field in the June tests. The results are somewhat similar, especially as far as backline players and loosies are concerned (the preference for loosies being May and June, it would seem!), but interestingly enough it does not hold for the Tight 5. In case of the latter I can only presume that it illustrates something that we already know about the T5 – they develop later and therefore date of birth does not play a role.
Also, this is a small sample and a more in depth look may turn up something else.
| Gri | Zim | Brd | WP | Pum | BB | KZN | Lim | Bol | EPCD | Leo | GCD | BCD | Val | Grf | Lio | SWD | EP | FS | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Jan | 2 | 5 | 4 | 4 | 2 | 4 | 3 | 5 | 3 | 2 | 4 | 0 | 3 | 1 | 3 | 4 | 2 | 2 | 3 | = | 56 |
| Feb | 3 | 3 | 2 | 4 | 3 | 3 | 3 | 2 | 1 | 1 | 2 | 2 | 2 | 1 | 4 | 0 | 2 | 6 | 4 | = | 48 |
| Mrt | 6 | 3 | 2 | 1 | 5 | 5 | 1 | 3 | 3 | 4 | 2 | 0 | 1 | 4 | 4 | 6 | 4 | 2 | 3 | = | 59 |
| Apr | 1 | 2 | 1 | 1 | 1 | 2 | 4 | 4 | 0 | 3 | 2 | 1 | 1 | 3 | 1 | 3 | 2 | 1 | 1 | = | 34 |
| Mei | 4 | 3 | 1 | 2 | 2 | 1 | 2 | 3 | 3 | 2 | 3 | 2 | 1 | 1 | 0 | 2 | 4 | 5 | 2 | = | 43 |
| Jun | 2 | 2 | 3 | 3 | 3 | 4 | 1 | 3 | 0 | 0 | 1 | 2 | 2 | 5 | 4 | 3 | 3 | 3 | 2 | = | 46 |
| Tot: | 18 | 18 | 13 | 15 | 16 | 19 | 14 | 20 | 10 | 12 | 14 | 7 | 10 | 15 | 16 | 18 | 17 | 19 | 15 | = | 286 |
| %: | 82 | 82 | 59 | 68 | 73 | 86 | 64 | 91 | 45 | 55 | 64 | 32 | 45 | 68 | 73 | 82 | 77 | 86 | 68 | = | 68 |
| Jul | 0 | 1 | 2 | 1 | 0 | 1 | 2 | 1 | 2 | 2 | 2 | 3 | 4 | 1 | 2 | 1 | 0 | 0 | 1 | = | 26 |
| Aug | 2 | 0 | 1 | 3 | 2 | 1 | 4 | 1 | 2 | 5 | 1 | 4 | 0 | 3 | 1 | 1 | 2 | 0 | 2 | = | 35 |
| Sep | 1 | 1 | 0 | 1 | 3 | 0 | 1 | 0 | 2 | 1 | 2 | 1 | 0 | 2 | 1 | 1 | 1 | 1 | 1 | = | 20 |
| Okt | 0 | 0 | 2 | 1 | 1 | 0 | 0 | 0 | 5 | 0 | 1 | 2 | 5 | 0 | 1 | 1 | 0 | 1 | 2 | = | 22 |
| Nov | 1 | 2 | 2 | 1 | 1 | 0 | 0 | 0 | 1 | 2 | 1 | 3 | 2 | 0 | 0 | 0 | 1 | 0 | 1 | = | 18 |
| Des | 0 | 0 | 2 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 2 | 2 | 0 | 1 | 0 | 0 | 1 | 0 | = | 11 |
| Tot: | 4 | 4 | 9 | 7 | 7 | 3 | 8 | 2 | 12 | 10 | 8 | 15 | 13 | 6 | 6 | 4 | 4 | 3 | 7 | = | 132 |
Springbokke (Julie-toetse):
Willie le Roux – 18/8
Bryan Habana – 12/6*
Bjorn Basson – 11/2*
JJ Engelbrecht – 22/2*
Jean de Villiers – 24/2*
Jan Serfontein – 15/4*
Morne Steyn – 11/7
Patrick Lambie – 17/10
Ruan Pienaar – 10/3*
Piet van zyl – 14/9
Jano Vermaak – 1/1*
Francois Hougaard – 6/4*
Pierre Spies – 8/6*
Willem Alberts – 11/5*
Francois Louw – 15/6*
Arno Botha – 26/10
Marcel Coetzee – 8/5*
Sya Kolisi – 16/6*
Flip vd Merwe – 3/6*
Juandre Kruger – 10/9
Eben Etzebeth – 29/10
Jannie du Plessis – 16/11
Coenie Oosthuizen – 22/3*
Tendai Mtawarira – 1/8
Trevor Nyakane – 4/5*
Adriaan Strauss – 18/11
Bismarck du Plessis – 22/5*
Chiliboy Ralepelle – 11/9
Jan-Jun: 17(60.7%) [Agterspelers: 8(67%), Losvoorspelers: 5(83%) ]
Jul-Des : 11(39.3%) [Vaste5: (60%)]
@Ploegskaar: Ek droom nou een aand van ‘n garage vol groot bokse. Toe ek wakker word, dog ek by myself. Dis bog!
@McCulleys Workshop: I wasn’t suggesting that there was – my point on conversion rates was simply to illustrate that notwithstanding the extra attention star players receive at U13-15 level there is still opportunity for players to come through and succeed from the lower teams which belies the conclusion reached in NFL studies that it is the extra attention that determines later success.
Pat Lambie is a good example of age not being that important – his birthday is towards the end of the year and he played Craven Week and made the SA schools side in his U17 year at a time when he was still 16.
@BOG: Your usage of the Boeing 747 analogue, similar to the blind watchmaker one, has the fundamental flaw of comparing the manufacturing of human artefacts with what happens with biological life.
You speak of science manipulating data, my friend, it first shows a completely misunderstanding of the scientific process and how it functions and when it comes to manipulation, nothing beats clergymen.
Galileo is the conscience of religion, for what they’ve done to him on something that we all accept today as the truth, heliocentrism, but it took the idiots more than 400 years to apologise.
Please don’t fall into the same trap of fixed ideas.
@BOG: Oom, have to admit that I am not much for alchemy and astronomy myself, but it does seem as if the stars have not aligned so well for your favourite teams the past 2 years. Do you believe in karma though, Oom?
Who falls
@meadows: Meadows, I don’t believe there is any statistical merit in looking at u13’s progression to u18. Each age needs to be viewed on its own merit for there to be any statistical correctness. I.e what where the monthly age bands every year for the last 10 years of the CW u13 sides, not the conversion to who ended up playing first team rugby. Therefore if the CW u13 side is on average made up of 70% boys who have their birthday in the first half of the year, one can understand and agree that there is merit in the stat. The same can be said about applying the same research to the CW u18 side, but it is unrelated to who went through from u13 – u18. What is even more interesting is the personality profile of the player who was born in the second half of the year, who defies the stats and at any age group is a high achiever – like Pat Lambie, wh ovals into this catagory. Maybe this is where guts, determination and BMT come in?
@BoishaaiPa: Your diatribe does not warrant a response. It also confirms much of what you have to say. Perhaps, the mothers of the boys taller than 2 mtrs, left their food, when younger, on a high shelf, where they had to stretch for the food- LOL Or perhaps, according to your logic, a Boeing 747 did have its origins after a dust storm in a garbage dump.
@BOG: Your logic and thinking towards evolution explains a lot about your comments here..It certainly makes your blind devotion to particular institutes understandable!..I will in future remeber this when trying to converse with you.
@Gungets Tuft:
Sure, call it blended – don’t think the statisticians will mind! But hang on, if it is blended it means it is half correct and we don’t no that yet!! Statisticians will definitely mind. So if we want to get away from statistical terms, let’s just stick to perceptions from a small sample more often than not create wrong conclusions.
To all the Western Cape bloggers:
I know it is just the beginning of the season, but I have to mention this as it is not happening a lot:
Cheetahs u.21 18 WP u.21 16 (Yes Kolbe and all the top players played)
Cheetahs u.19 18 WP u.19 18
@Djou: Please can we make that “blended” noise esor ….
Guys you are missing one crucial point.
Date of birth definitely plays a role, especially up to u.16-level. Thereafter most boys catch up. Lots of research studies available to prove it. Therefore you constantly find victory scores of 70-0 at u.14-level changing into losses at senior level.
However, it is not just the age factor – four to five months the boy is older – that make the difference. It is also about the additional training, the extra hard hours the boys put in.
Gladwell showed that the additional training received by the “older” hockey guys as a result of being called up to national training squads provided them with more skills compared to the younger guys.
The additional training is not so big in SA SBR. Only really starts from u.16-level upward.
That being said, you need a sample much longer than one year in order to arrive at a definite conclusion. Otherwise the results are what is termed white noise.
@meadows: Granted, the low conversion rates from U13 might indicate that the school sport ethic in SA, rather than club/College system in the US makes some sort of difference. Critics might argue that the low conversion rates are more in indicator of poor selection policies, kids that just get missed at junior levels because they go to the wrong schools, outside the metro areas and just don’t get noticed. Once at high school they get more exposure and start to show up.
It would be really interesting to do the same exercise at U13 level and see what the data shows.
IT would be even more ineresting if the kids born under the sign of Aquarious were better swimmers …
Sorry ou Bog, ek spot maar net jong, dis nie n horroscope dingus die, net n ouderdom ondersoek ….
Malcolm Gladwells, “Outliers” also gives a good insight into this subject
@Gungets Tuft: The advantage obtained in those formative years by being in the A team (or perhaps more importantly “on the team”) was considered the most important factor in research on this subject that came out of football (NFL) in the US.
I’m not sure how much one can infer about rugby player development in SA from this, given the structural differences between the two sports and environments, but the dates of birth in the article above seems to provide some anecdotal corroboration.
The relatively low conversion rate of U13 Craven Week players to even Craven Week level and the number of later developers that come through at around 16 years of age does seem to suggest that early (<16) development and training advantages are not as important in rugby in SA as perhaps they are in NFL in the US. I suspect that many high school football programs do not cater for B, C and D teams were a late developer may emerge from in his mid teens at a SA rugby school.
@BOG: Ahhh, Boggie, the old denial trick of just stating that the stats produced by Gladwell and by Tzavosky are pagan religion, instead of actually looking at them and discussing them rationally. It is not pagan, it is a theory. Nobody has said they are “blessed” in any other way than simply (at age 10 for instance) being up to 9% bigger and more developed and how this affects their progress. Any argument with this, other than you don’t like it?
Have you read Gladwells book, have you actually looked at the numbers in this article – with as open mind as you can, given that you have already dimissed the reasoning as anti-whatever-religion-you-think-it-is-anti?
@BuffelsCM: But the “difference” that never goes away in team sports is that those in the A teams at U10 – U13 get the best coaching, while the kids in the lower teams do not. The A teams get more game time, go on the tours, play the best opposition. In general, those kids get a massive advantage in those formative years. For a kid to catch up later they have to have talent that is extraordinary. It happens, about 25% of the time, that the late born kid come through, but they have to work that much harder, and keep motivation up while they grow into the size ranks and battle up the teams to the best coaching (again).
I could refer to a very relevant Book, where much is explained. But consider reading the many books written by Dr Andrew Murray, the first principal at Grey . His books are still, to this day re-published internationally. With 7 billion people living on the globe, you are going to find substantial numbers to confirm almost anything. Even those with a freckle, two millimetres left of the left eye. What Im saying is that we can confirm almost anything with dates and numbers- it depends on what we want confirmed. Believe me, “science” is no exception. I can for example show how data is being manipulated to “prove” evolution while while it is being spoon fed to many children as exact science- massive deception. But while I am not afraid to go down that road, I dont think that this is the platform to do so. It may just be in contravention of “house rules” But likewise, , we need to refrain from pagan religion, presented here as “science”.
I think the month of birth plays a definite role. My son used to be a tennis player. It didn’t affect him because his birthday is in May. A good friend’s daughter was born on 25 December. She often had to play girls in her age group that were born during January or February which would give her a disadvantage of about 10 or 11 months.
When you are 13, 14 or 15 years old it makes a massive difference. At a later stage, say 16 or 17 the difference will not be as huge though.
In a physical and contact sport like rugby there is an obvious advantage when born in January in contrast to say November or December….my 2 cents
@Gungets Tuft: Read that book too. Great read. Boggie raak die topic te tegnies? Jy’s die ou wat bietjie slack gevra het. Nou is jy weer katjie (‘n klein cheetah katjie van die baan). Lyk my jy voel weer ryk en lui? Derhalwe die deelname. Ons almal het nog die Vrystaatse prestasie vars in die geheue. Op ‘n ernstiger noot. Voel jy soms om uiting te gee aan jou gevoelens as dit volmaan is?
Being born early in the year is definetly an advantage. At senior primary level kids are often chosen on size and unfortunately this trend is becoming more and more in high school to. Big kids get the bursaries the recognition etc. What is always amazing to watch is how these kids are nullified when the other kids get to there size or thereabouts. One thing that should always be looked for is ball handling and ball sense. A classic example for me is deon fourie from province not the biggest of players but what an impact he has saturday after saturday. I beleive that today to much emphasis is on size and not enough on real ability.
I think the main reason for the amount of players that perform, which were born before July, can be the following. When in primary school, size is almost all that count and if someone is born in Jan and another kid is born in Dec, the one born in Jan will for sure be bigger and stronger. The one born later will then over time not be in the “A” teams and the other will build a repuation that will always stay as he goes through the different age groups. The younger one will lose interest as he is always”behind” and will not put in so much effort to make “A” teams. I see this alot and surely it play a roll in the % of players making it, even in school.
@BOG: BOG – if the age group cut off is June or July (like it is in some northern hemisphere countries due to the staggered mid year school year start) – then the age distribution works in the second half of the year. It is about the kids having a six month growth advantage over their peers in the same age group.
Obviously a generalisation in that it is not universally true – but it does hold true. I was fortunate to be a November baby and still be relatively bigger than average through school – so did OK. But I do agree that this is a correct notion and has much scientific and statistical proof in many different codes and countries to back it up. Especially in the physical codes (ice hockey, rugby, basketball etc.). Not sure it would hold for cricket or swimming etc.? That I do not know.
Great article.
@BOG: It’s not “dark science” ou Bog. Get a copy of “Outliers” by Malcolm Gladwell and read, even if just the first chapters. There is a very logical and non Sangoma explanation of the effect. It’s all science and sociology and easily applied to the way mini-rugby and primary school sports teams are picked.
If ever there was a pagan view, then this is one. What about the effect of full moon? Are such people more inclined to howl or bark at night when the moon comes out than others? This may even prove to be correct, depending on how the facts are manipulated to ensure the “desired results”. How about throwing the bones, reading the “stars” or depending on “luck”? At least this explains the absurdities that we so often read here. I could elaborate further but then of course, I may just be accused of talking “religion” on a rugby blog.
@Koos Roos: Net soos jy daar sê, Koos, dit het te doen met die RAE, maar interessant dat die Bokke ‘n soortgelyke patroon toon, hoewel dit ‘n baie klein toetsgroep is.
Die ander interssante ding wat ek raakgesien het met die CW-spelers is dat dit ook geldig is vir die outjies wat nou Gr 11 is – al is hulle ‘n jaar jonger, verjaar hulle meestal in die eerste 6 maande.
Van die huidige SA Skole groep verjaar 75% in die eerste helfte van die jaar, so dit smaak my ‘n voornemende ouer wat sportaspirasies vir sy toekomstige kind het, moet maar goed beplan!
@Koos Roos: The discussion came up on the blog earlier this year and I also read the summary of the research on the Canadian ice hockey team and subsequent studies that disproved it and others that poked holes in the research assumptions made. All very interesting as is this analysis above which suggests that almost 70% of the players are born between Jan-Jun.
Wat verder interessant is, is datdit afhang van die seisoendatum. Yshokkie in Kanada is van Jullie tot Desember. Teenstrydig met vroee navorsing is bevind dat meer suksesvolle spelers laat in die jaar gebore is, want die seisoen begin eers teen Jullie. Dus begin hul afsny punt daar. Gevolglik is die spelers in daardie ouderdomsgroep ouer en meer ontwikkeld. In die SA model van rugby, sal dit dus die kinders wees wat in die eerste deel van die jaar gebore was, want ons afsnypunt is Januarie. Gevolglik is daardie stats min of meer presies dit.
Beet, my seun moes ‘n projek hieroor vir LO doen. Het toe artikels gelees wat my nogal iets geleer het. Hulle gebrui ‘n term RAE (Relative Age Effect) wat ‘n studie behels oor die effek van kinders se ouderdomme en vlak van ontwikkeling aan die hand van sy geboortedatum. Dis egter net relevant tot ouderdomsgroepe. Iets soos die Bokke se verjaarsdae sal irrelevant wees.
Ek is in Junie gebore en dit het beslis tot my rugbyhoogtepunt, onder 19F, bygedra. Boonop was ek kaptein. In std 9 het ek ook vir die Goffels, Hommels en Idiots uitgedraf, dis die G,H en I spanne. Junie is beslis ‘n goeie maand om te verjaar as jy rugby speel.