Key Number
A margin that occurs disproportionately often. In the NFL, 3 and 7 are the biggest key numbers.
A key number is a winning margin that comes up far more often than statistical averages would suggest, due to scoring conventions.
NFL key numbers (in order):
- 3 — field goal
- 7 — touchdown + extra point
- 10 — TD + FG
- 6, 14, 17
Roughly 15% of NFL games are decided by exactly 3. Roughly 8% land on exactly 7. That’s why moving a spread from -3 to -3.5 costs a meaningful amount of juice — the book is selling you protection against the most common margin.
NBA, MLB, and NHL key numbers are less pronounced. NFL is the sport where key numbers matter most.