Power

Moves with more power inflict more damage. Statistically, the more damage a move inflicts, the more likely it will either have a lower accuracy, a negative effect for the user like recoil damage, or a lower PP (though some strong outliers exist, such as Extrasensory; these are often signature moves). How much power a move has can be seen in the Pokémon stats screen, in the move section, along with accuracy.