What Is Left Coverage Rate?
Left coverage rate measures the share of a defender's routes defended where the receiver he was covering lined up on the offense's left. Sides are named from the offense's point of view throughout, so a corner with a high left coverage rate is physically stationed on the defense's right. Read it as a travel indicator: corners near the extremes stay on one side of the formation every snap, while a figure close to even means the defender either follows a particular receiver across the field or rotates through the slot. Left and right coverage rate add to very close to 100%: the denominator is the same charted receiver-alignment population the numerators come from, and the roughly one percent shortfall is routes on plays whose formation does not resolve a side, excluded from both rather than guessed.

