How venues inflate or suppress offense. A runs factor above 1.000 means the park produces more runs than average; below 1.000 means fewer. Computed from home/away run differentials across all games played at each venue.
Runs factor ≥ 1.050. Thin air, short fences, or dry climate conditions that boost offensive production.
Runs factor between 0.950 and 1.050. No significant offensive skew in either direction.
Runs factor ≤ 0.950. Dense air, deep outfields, or marine climate that suppresses offense.