Stat SOO

SOO (Strength of Opposition)

We created the SOO Rating to provide some reliable indication of how tough a pitcher's opposition has been over the stretch of his season pitching assignments. The SOO rating ranges from 3.0 to 6.2. The higher the number the tougher the pitcher's opponents have been. SOO's most reliable use is for comparing pitchers on one's own staff. It helps us to understand whether a pitcher's performance has been affected by disproportionately easy or tough assignments.

How do we derive SOO?

When a pitcher exits, the sim calculates the average runs per game (RPG) of the opposing team and then weights it by the exiting pitcher's TBF (total batters faced) for the outing. The results of every outing are stored and accumulate through the season.

This formula is applied after each outing such that the numerator and denominator grow throughout the season.

 (RPG * Pitcher's TBF) / TBF

No opponent's RPG is generally permitted to go below 3.0 or rise above 6.2. This keeps the SOO rating from gyrating wildly in the early part of the season. Why 3.0 and 6.2? Because these numbers when projected over a 162 game season will represent roughly the highest and lowest team run production totals we'd expect to find in a league of distributed talent (6.2 * 162 = 1004 total runs, while 3.0 * 162 = 486 runs). While it's conceivable that a team could produce an RPG of higher than 6.2 or lower than 3.0 over the course of the season, these numbers are assigned as the upper and lower boundaries of the SOO Rating.

Note in the image below how after 5 starts the pitchers vary in the difficulty of their opposing lineups. Camilio Pascual has faced the toughest opposition so far. Opposing lineups have averaged 4.2 RPG.