Measuring Goalkeeper Impact in MLS: A Data-Driven Look at Value, Volatility, and Efficiency — American Soccer Analysis By Lucas Morefield Goalkeeper evaluation has always been one of the thorniest challenges in soccer analytics. The position is defined by small sample sizes, high variance, and context-driven outcomes...

Dayne St. Clair joined Inter Miami as maybe THE marquee free agent in the market. @morefie.bsky.social looked at the volatility of GK metrics and how important the starting goalkeeper salary slot really might be.

www.americansocceranalysis.com/home/2026/1/...

The 2026 NWSL College Prospect Dashboard — American Soccer Analysis It’s that time of year, where the world’s best women’s soccer academy system drops 100+ prospects onto the world’s clubs. Fortunately, there is no longer a draft in NWSL forcing the best players to p...

There’s no draft in NWSL but teams sure are signing players out of college.

So @paulharvey.theoutfield.nyc made the NWSL college prospect dashboard.

www.americansocceranalysis.com/home/2026/1/...

And in the end, key variables like goal diff, possession length, etc. are still accounted for without overweighting certain teams.

This assumes that the underlying xPV framework is fit with some sort of model (anything from OLS to neural network). Then weights can be submitted and applied to the optimization function. Guarantees that the teams that get to “good” states are not over represented in those states.

Team proxies = great callout. I propose, instead of removing the proxy variables, control for them. Creat clusters based on team proxy variables at the row level. Within each cluster within each season, weight the rows such that each team is equally represented. Submit weights to ML optimization.

Using prior week's lineups, g+ saw WAS as +0.3 goals better than LOU on roster g+ alone. That said, WAS has allowed 1.4 xG in open play vs. LOU's 0.55, which mostly offsets that advantage; model now sees both teams as ~equal. Home effect for LOU + WAS injuries = 50% home win probability.

I spend 12% of my time coding and 176% of my time screwing up environments.

American Soccer Analysis

The MLS previews are done, thanks to everybody who wrote, shared, tuned in.

If you missed some, they’re all here: www.americansocceranalysis.com/home/categor...

So, about those anonymous soccer analysts Minnesota are working with... www.americansocceranalysis.com/home/2025/3/1/american-soccer-analysis-announce-minnesota-united-fc-as-analytics-consulting-client

?

Perhaps fittingly, first post here is about using our API to get free soccer data!

R readme: github.com/American-Soc...
Python: github.com/American-Soc...

Was just working with an ASA friend to derive a relationship between g+ and compensation, supported by data completely available thru the API!