Why football has key numbers
Football scores mostly arrive as field goals and touchdowns, so a large share of games end with a margin of exactly 3 or 7. Moving a spread from −2.5 to −3.5 crosses one of those landing spots, which is why it's priced so heavily.
Why basketball is flatter
A college basketball game has well over a hundred possessions between the two teams, each worth zero to three points (or more with free throws). That many small scoring events smooth the distribution of final margins. No single number collects the share that 3 does in football, so a half-point on most basketball spreads is worth less than the same half-point around a football key number.
Where margins do bunch up
- Close games are more common than blowouts, so numbers in the low single digits see more landings than numbers in the high teens.
- Late-game fouling and free throws can push close games out to a few points, which is one reason the end of a game moves margins more than the middle.
- Overtime adds points to both sides; check whether your bet includes it (most full-game markets do).
Totals are similar
Final totals in college basketball also spread widely, so there's no small set of totals that dominate. A half-point matters most when it decides whether a total lands on your number (a push) or past it.
What to take from it
Don't pay a big price to buy half a point on a basketball spread the way you might in football. Do still shop for the better line: over a season, the landings add up (line shopping).