The Ballpark Pal model evaluates every pitch thrown to each batter throughout the season. Every pitch has an expected outcome based on its physics (velo, break, spin, location, etc.). These expected outcomes serve as the baseline for evaluating the hitter's performance. In other words, a hitter gets penalized more if he doesn't perform well against the easiest pitches to hit. He gets rewarded more if he hits tougher pitches.

The model also ignores batted ball outcomes, since they can be random. Instead it predicts what the outcome should be based on exit velocity, launch angle, and direction. This helps control for weather, park factors, and general randomness.

The score is an "expected runs created" metric based on how the various outcomes (single, walk, home run, etc.) relate to scoring runs. It uses fixed values for each outcome and ignores factors the hitter can't control such as runners on base.

Higher scores are GOOD

Lower scores are BAD

Ballpark Pal simulations use a "matchup model" to predict the outcome of a batter/pitcher matchup. The model uses dozens of characteristics for both players to produce a probability distribution of outcomes (shown below).

BF: Number of batters faced by the pitcher this season

H: Handedness of the pitcher

%ile: Every pitcher is lined in up in order from 1 (least favorable matchup for the batter) to 100 (most favorable). This corresponds to the percentile slider shown beneath the pitcher on the Matchup Machine page.

Adv: The Advantage from the batter's perspective. Postitive 10 indicates an extreme advantage for the batter. Negative 10 indicates an extreme advantage for the pitcher.

Hit: The model's likelihood that the batter will get a hit

K: The model's likelihood that the batter will strike out

BB: The model's likelihood that the batter will walk

HR: The model's likelihood that the batter will hit a home run

IPO: The model's likelihood that the batter will record an in-play out

2B: The model's likelihood that the batter will hit a double or triple

1B: The model's likelihood that the batter will hit a single

History (Actuals): The actual results from plate appearances during the last 3 years

History (Model): A model predicts the outcome of every ball hit in play based on how it leaves the bat (exit velocity, launch angle, direction, and batter handedness). This helps control for luck, weather, and the park the hitter was in.

Green is GOOD for the batter

Red is BAD for the batter