Population Pyramid of Scottish 6 Day Orienteering Entries

Here’s a population pyramid of the entries so far for this summer’s Scottish Six Days (S6D) orienteering event, based on the 2000-odd people on the entry list shortly after the cheap entries’ closing date.

At first glance it looks like the demographic is horribly unbalanced. There is definitely a “hole” in the middle! However, there are some possible mitigating factors:
1. Older people might be more keen on entering early so that their plans for the summer are organised well in advance. Younger people are less organised?
2. Younger people are maybe more likely to be injured due to their faster running speeds, so only want to enter when they are more confident of being injury free?
3. Younger people’s incomes are more vulnerable to change so they are waiting to enter closer to the event (£90+ entry fee for the six days) when they are sure they can afford it?
4. Older people are more affluent and so happy to enter a long time in advance and then maybe not show up?
5. Leave is harder to arrange for younger workers?
6. Younger people are more weather sensitive and want to see what sort of summer it’s going to be in a notoriously wet (or midgy) part of Scotland, before entering?

Here’s what the Office of National Statistics’ population pyramid for the UK population for 2011 looks like – you can see this for yourself at the ONS website:

Bear in mind that this is just the UK population, and 20% of the entries for the S6D so far are from foreigners. The age axis for the ONS pyramid starts at zero.

(N.B. The ages for the S6D pyramid are based on the age at 31 December, rather than at the event date in August. Ages are also averaged through the age bands – 2-year for juniors, 5-year for vets – for which the data is available. I have assumed that all the M/W10s are aged 9 or 10.)