In Both Teams to Score (BTTSi, GG in Greek) you win if both sides score, whatever the final result. In No Goal (NG) you win if at least one team stays at zero.
What to check
- How often each team scores and how often it is held to zero.
- Whether one side is much stronger: then the weaker team often does not score.
- Missing goalkeepers and defenders.
- Motivation: a decisive match often closes up.
Example
If the model gives team A a 70% chance to score and team B 60%, treated as independent, the chance of BTTS is 0.70 × 0.60 = 42%. The odds must be above 1 / 0.42 = 2.38 to be value.
In practice the two events are not independent: an early goal opens the game. That is why models such as Dixon-Colesi adjust the low scores.
BTTS and Over 2.5 move together but are not the same bet: 3-0 is Over and NG.