Reply to MLS Next Quality of Play scores make no sense

Forum Index » Soccer

Reply to "MLS Next Quality of Play scores make no sense"

Subject:

Emoticons





More smilies

Text Color: Font: Close Marks

[quote=Anonymous]The quality of play algorithm uses the “quality of every significant player action” to calculate attacking and defensive scores. This seems to work reasonably well for attacking, but it can lead to the wrong results for defending. Let me give you an analogy: you are comparing hospitals A and B on how well they treat infections. Hospital A admits 100 patients, 50 get infections at the hospital, and 5 die. You conclude that hospital A treated 45/50 infections successfully for a success rate of 90%. Hospital B admits 100 patients, 5 get infections, and 3 die. You conclude that hospital B treated 2/5 infections successfully for a success rate of only 40%. If you only look at success rate, you will conclude that hospital A is better. But hospital B actually prevented infections and that led to fewer total infections and fewer deaths.

Something similar might be happening for defensive quality of play. I will use Achilles U14 as an example because they have one of the largest differences between goals allowed and defensive QoP, but there are many other examples. Achilles likes to build from the back and play through the middle. That might be great for development and might produce great players 5 years from now. But for now, it leads to a lot of turnovers in their own half, high possession for the opposing team, and a lot of high quality defensive actions for Achilles’ CB and CDM. They allow 3.55 goals per game and their defensive QoP is 80.6. They are like hospital A.

Baltimore Armour (0.47 goals allowed per game), SYC (0.74 per game), Philly Union (0.84 per game), Delco (1.26 per game), allow fewer goals per game than Achilles – Armour allows 7 times fewer! Yet they all have a  worse defensive quality of play than Achilles. This is not because their defenders are bad. This is because these teams prevented attacking opportunities from their opponents by either having more possession, recovering the ball farther up the field, or other actions. They are like hospital B.

Baltimore Armour U14 has the second fewest goals per game allowed in the country (0.47), but they are ranked #73 in defensive QoP. Cedar Star Bergen has the third fewest goals per game allowed in the country (0.53) but they are #51 in defensive quality of play. These teams are likely being penalized for having fewer high quality defensive plays than other teams, but that should actually be a good thing! Again, these teams are like hospital B.

I think this is a reasonable explanation for why defensive QoP seems uncorrelated with goals allowed. It rewards high quality defensive plays but also rewards having a high volume of defensive plays. It penalizes teams that have a low volume of defensive plays. But I admit I could be wrong. Taka’s algorithm is proprietary, non-public, and not reproducible. I have no way to test these results with their data. But if anyone from Taka or MLS Next eventually reads this thread, maybe they can look into how defensive QoP is calculated next year.
[/quote]

Options

	Disable HTML in this message
	Disable BB Code in this message
	Disable smilies in this message

Review message

Search Recent Topics Hottest Topics