Attacking vs defending probability?

[gmagnus]

Is there any probability advantage in being the attacker or the defender in a large army battle. I've been in situations where I've sat my 15 strong army next to the border of someone else's similar army. I've always wondered whether its better to always attack first, or whether it might be better to let them attack me.

Mathematical help please...

[Jafnhár]

See

http://en.wikipedia.org/wiki/Risk_%28ga ... babilities

[tahitiwahini]

The attacker has a 7.91% advantage over the defender.

Assumptions: attacker has sufficient armies (4 or more) to throw three dice, defender has sufficient armies to throw two dice (2 or more), so the attack is 3 v 2. The more dice you throw the better your chances of winning an attack (even though ties go to the defender).

It's always better to attack than defend, except when the defender can match the number of dice the attacker can throw.

http://www.conquerclub.com/forum/viewto ... 035#270035