
Show HN: Compare soccer players by their influence on the result - monodeldiablo
https://kxrank.com/
======
yimoburu
Looks interesting, But what is this used for? And how should people understand
the 'influence'?

~~~
monodeldiablo
Clubs and agents can use it for scouting and player valuation, managers can
use it for team selection, and anyone can use it to follow a current player's
effectiveness on the field (paying customers get access to ~250,000 players
globally).

As for "influence", our model measures the amount a given player impacts their
team's odds of winning. Players with higher scores are more likely to tilt the
odds in their team's favor when they're on the field.

We created this metric because most soccer models focus on discrete event
statistics (passes, shots, expected goals, saves, blocks, etc) that paint an
incomplete picture of a player's absolute quality.

There are some players (like the players currently in positions 3-6 in
kxrank's top 100 list) who don't stand out statistically, but whose teams
nevertheless are _substantially_ more likely to win when they're playing
versus when they're on the bench.

Does this answer your question(s)? Do you think we can document this better on
the site?

~~~
stfwn
On HN people often like to see the math. It's very understandable that you
would keep the secret ingredient, well, secret. But readers are just looking
at a opaque magic number now.

~~~
monodeldiablo
Of course, I can't just link the model code (even though I'd love to!), but
it's not just for reasons of secrecy that we use an "opaque magic number".
_All_ semi-sophisticated ranking systems wind up being opaque magic numbers.

We can't, for example, express a player's impact in terms of raw odds, because
those odds are also determined by the level of their teammates and the
opposition players. For the same reason, we can't express this number in terms
of goals or points or any other easily-mapped statistic.

So we need to use an abstract points system -- just as Elo and Fargo and other
player rating systems use -- as a means of tracking and ranking player impact
over time.

However, right before kickoff -- when all the players are known from both
teams -- we can distill those ratings back down to odds/goal/point advantages.
This is, in fact, how we wagered with the model.

