Introducing squad age profiles

It’s been a while since I created a new type of graphic and I want to try and address that with as much new stuff or improved stuff as possible in 2021.

I’ve picked something relatively challenging to start off with, which I’ve been kicking around for a while now. What I wanted was a more detailed squad age profile for each club to accompany these funky charts. Specifically I was after something which gives a single-screen overview of a club’s balance between age and experience across the pitch, breaking down:

  • The current age of each player,
  • The share of time they’ve spent on the pitch, and
  • What their primary position is.

The minutes played vs. age charts that Tom Worville produces for the Athletic (example below) do most of what I’m after, but I’ve made a few alterations to fit what I needed.

The main thing I’ve done differently is to split players up by position, as for clubs I was less familiar with I found myself struggling to quickly pick out interesting areas of the team. Another advantage of doing this is that you can calculate peak age (the red stripe in Tom’s chart) differently e.g. goalkeepers will usually peak later than wingers.

Here’s an example of my template – apologies it’s a bit tall as I’ve opted for a portrait orientation designed to fit a phone screen.

Player positions

I ended up using a combination of Football Manager 2021 and TransferMarkt position data to categorise each player, and based on how well the age distributions correlated I rolled these up into six main positions. It’s not perfect by any means (e.g. defensive and attacking central midfielders are in the same category), but I had to make some compromises to keep things manageable.

There’s an obvious drawback here which is that some players are capable of playing in more than one position and can be deployed in multiple roles during a season. When I’ve spotted this I’ve tried to categorise them using their primary position, even if they’ve been played somewhere else for the majority of the season. However if you think I’ve got something wrong then please let me know.

Age distributions

There were several ways I considered to work out the peak ages, so I settled for the most transparent option I could think of. What I’ve done is to analyse every match in the Premier League and EFL over the past five complete seasons and work out the share of minutes accumulated by players of each age in each position.

The resulting distributions are what you can see in the background of each plot. These are independent of the percentage scale – they’re intended to indicate the proportion of playing minutes that players of a given age in that position tend to get, relative to those who are older or younger.

For example, a grey bar that completely fills its column doesn’t mean that players of that age typically play 100% of minutes, but rather that recent history suggests they’re the most likely to do so.

Average ages

You’ll see that I’ve also calculated the average age for each part of the team, weighted by the number of minutes that each player has featured for. This is shown as a coloured line on each chart in addition to the label above it (a great suggestion by Steve Jones).

Other considerations

Initially I was bringing every player who had stepped onto the pitch in the league onto the graphic but this led to some sections getting too crowded to be easily legible. I’ve therefore excluded players from the plot if they’ve featured for less than 5% of their club’s league minutes this season, which seems to give the best balance.

Next steps

I’ll follow this post up with a full batch of graphics for each division, from which I fully expect feedback on player positions at the very least. I’ll then roll any data updates up with any design feedback into a second batch.