A few weeks ago, we introduced Expected Possession Goals (xPG) GameFlow, a visualization of the momentum of a soccer match from kickoff to final whistle of each game. xPG GameFlow uses the accumulation of Chance xPG to measure the strength of an opportunity for a team to get a shot. The higher the Chance xPG differential between the teams, the longer the bar for that minute for the team with the higher amount. Quite often goals are scored when the momentum bars on the xPG GameFlow chart are at their longest.

Many people have asked us, “what is the difference between xPG and xG?” or “how does xPG translate to xG or to goals?” To aid xPG GameFlow in answering questions such as “which team had the better chances?” and “when should a team have scored?”, we introduced a couple improvements after the first week of tweeting MLS game charts on @GameFlowxPG. I wanted to provide more context for these improvements and dive deeper into them.