xPG is Back, Baby!: Putting Possession Metrics to the (Correlation) Test by Jamon Moore

Last year, Cheuk Hei Ho, Eliot McKinley, and I collaborated on a soccer metric called Expected Possession Goals (xPG). xPG is a possession-based non-shot expected goals metric designed to measure the value of possessions whether they result in a shot or not. You can read more about it in these initial articles here on American Soccer Analysis. Later last season we extended xPG into multiple variants, including measuring possession risk and mistakes, but so far the initial xPG, now called Chance xPG, has been the most interesting. We even created a Twitter account called @GameFlowxPG which measures match momentum. It has been pretty popular (I’m a little salty since it usually has more followers than I do).

Read More