Found this post by Andrew
“ It's approximated by a 24 hour half life exponent formula for all servers except express. Express has an 8 hour half life I believe. Only 72 hours of history is considered (24 in express).”
“ Also I believe DH contributes as half of a break. To implement this I would calculate the DR contributions of each attack and sum the last 72 hours of news. Attack contribution to Dr = x*.5^(t/24) where x is 1 or . 5 depending on success or fail and t is the time in hours since the attack. t is a continuous number, not a round integer.
Hopefully someone will correct me if I'm wrong here. I know the exact calculation depends on forces sent.... But those can't be known so an as approximation is necessary.”
https://www.earthempires.com/...arth-news-central-52023/2