What Is Perimeter Rate?
Perimeter Rate measures the percentage of a player's dropback snaps taken on the boundary rather than inside, and it is the companion to Slot Rate: one counts the snaps a receiver spends in the slot, the other the snaps he spends outside. Outside alignments are where press coverage and a defence's top cornerback live, so a high perimeter rate describes a receiver an offence is willing to leave in one-on-one situations without scheme help, while a low one points to a player moved inside to find easier releases and softer coverage. Perimeter Rate sums both sides of the formation, so it pairs naturally with Left and Right Alignment Rate when the question is not how often a receiver lines up outside but which boundary he lines up on. For a wide receiver, slot and perimeter account for essentially every dropback snap. Tight ends and backs also take snaps in-line and in the backfield, which belong to neither, so for those positions the two rates will not add up to the player's whole workload.