Sometimes, players get advantage; sometimes, monsters get disadvantage. Sometimes it's not clear whether to give someone advantage or his opponent disadvantage, especially in improvised contests (PHB 195).
I know enough about statistics to know that "roll two, take highest" can produce tricky results. Therefore, I ask:
In a contest with otherwise constant bonuses, is giving one side advantage always equivalent to giving his opponent disadvantage?
This could matter e.g. if a player maneuvers a monster into an unfortunate situation. Now it feels better for the player to gain advantage, when more logically the monster is at a disadvantage.