Lots of things factor into successful actions.
Pots
Reset bonuses
Buildings
Equipment
Allies
Achievement bonuses
Clan bonuses
Propacks
Even your flag
The largest factor would a lot of the time be pots. As they add a static bta of 4m. Your stats would have to be greater than 4m to be a bigger factor, but the strength of your stats get weaker as you use up your bar.
So I'd say that it's pots.