What makes footy unpredictable?

The number of players, the roaming nature of the positions of these players, the free wheeling and (compared to other sports) unstructured nature make it a very hard sport to analyse in the same way we would look at cricket, basketball or other sports.

Many sports can be reduced down to individual players then built up into a larger whole. Understanding how well a player can hit a ball in baseball and comparing this to how well the pitcher can throw the ball can be added up over and over to give a reasonable idea as to how well a team of individual players will perform. The same applies to all sports played by individuals to varying degrees. A sport like cricket which is almost entirely the addition of different individual contests is on one end of the scale. Some sports are harder to build up from the individuals because so much of what makes a team successful is how the pieces fit together, not just the individual pieces themselves.

This isn't to say that individual players are not better or worse than others, just that footy is a sport where the whole is much more different to the sum of its parts.

There are individual contests within footy, but compared to other sports they are often harder to measure and occur within a much larger context of play.

Footy teams have 18 on the field (with 4 - 5 on the bench depending on how you define the sub). While each of these players will have positions (and will often have a designated opponent player), the game itself is nowadays played with all players existing in in the third of the ground surrounding where the ball is irrespective of their "opponent".

Sport	Players on field	Comments
Cricket	11	The sport is almost entirely just the summation of individual contests between bowlers and batters. Yes, there is something to be said about bowlers bowling together, how fielders interact and team synergy, the entirety of performance can be reduced to adding up the individual parts.
Basketball	5	Zones and systems exist, but the relatively small number of players on court, the small size of the court combined with the number of individual "actions" such as shooting %, points, assists, blocks, steals etc make it relatively easy to determine individual level of performance plus how these individuals contribute to team success.
American Football	11	More free wheeling than cricket and basketball, but the game is still much more structured than footy. The players are in specific positions such as QB or RB, with specific periods of attack and defence that allow much more minute and individualistic analysis to occur.

In short, while many sports analytics can be built up from individual contests and performances, footy requires an approach that looks at the system as a whole.

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