I think it might be easier to just link to the Bulbapedia page for it: Effort values - Bulbapedia, the community-driven Pokémon encyclopedia
To put it simply, it's gained from battling(or now through Super Training) and is used in the stat calculations. It's separate from level, but is used together(with a few other factors) to determine the final stats of a Pokémon.
To put it simply, it's gained from battling(or now through Super Training) and is used in the stat calculations. It's separate from level, but is used together(with a few other factors) to determine the final stats of a Pokémon.