WPA records the amount every PA changes the game, plus or minus, for both teams.
WPA is context dependent. It considers the score, the amount of outs remaining, etc; all the things we as fans consider.
On April 12th we hit 3 HR’s. O’Neill tied the game at 1-1 with a second inning HR for a +10% change in WPA.
In the 4th Arenado hit a 2run HR for +18% WPA, to go ahead 3-1.
By the top of the 8th it was tied 4-4. Gorman hits a 2run HR for +39% WPA.
3 different HR’s, but WPA values them differently due to the CONTEXT of the game. As BB would say, “when it matters”.