When two moves have the same priority, the Pokémon with the higher effective Speed usually acts first. Effective Speed can be changed by stat stages, paralysis rules, items, Abilities, weather, Tailwind, and other effects. If Speed is tied, the game normally chooses the order randomly. Priority moves are checked before Speed, so a slower Pokémon can still act first by using a higher-priority move. Trick Room reverses the usual Speed order for several turns, allowing slower Pokémon to move first among equal-priority moves. Speed is therefore one of the most important stats in both casual and competitive battles.