Settlement score is tallied when a settlement is completed, and contributes to the player's standing amongst other factions during the current blightstorm cycle. Factors include win/loss, total reputation gained, impatience left, maximum impatience level gained, orders completed, events completed, settlers lost to death or abandonment, total number of settlers, game length, and final wealth. A multiplier for difficulty is applied to all factors: x0.5 for Settler, x1 for Pioneer, x1.5 for Veteran, x2 for Viceroy.
Settlement score does not affect the citadel resource nor experience rewards for an individual win, but does indirectly affect the rewards at the end of a cycle.