Effort values, in the form of effort points, are gained in addition to bonuses gained by increasing level. Effort values ensure that trained Pokémon are stronger than wild Pokémon, even those of the same level. Effort points are awarded equally to all Pokémon who participated in defeating a Pokémon. Though they are shared, each of the Pokémon will receive the standard amount of effort points.
Yes, EVs add to a Pokemon's usual stats. There are a few ways to change a Pokemon's EVs, those ways are listed below.
- Defeating a Pokemon will give 1 - 3 EVs to certain stats. (You can see what Pokemon give which EVs here)
- Super Training a Pokemon's EVs in the stats you train them in will increase their EVs, using a Reset Bag on a Pokemon will remove all of the EVs from a Pokemon
- Using Vitamins will add 10 EVs to the Pokemon you use them on, what stat depends on the vitamin. (HP Up is HP, Protein is attack, Iron is Defense, Calcium is Special Attack, Zinc is Special Defense, and Carbos is Speed.) Vitamins cannot raise a Pokemon's EVs to over 100.
- Feeding a Pokemon an EV reducing berry will take away 10 EVs from it (Unless it has over 100 EV, where in that case feeding it an EV reducing berry will reduce a Pokemon's EVs down to 100.) and increase its friendship. (Pomeg Berries lower HP, Kelpsy Berries lower Attack, Qualot Berries lower Defense, Hondew Berries lower Special Attack, Grepa Berries lower Special Defense, and Tomato Berries lower Speed.)
- Giving a Pokemon a wing will add 1 EV to a stat. (Health Wing is HP, Muscle Wing is Attack, Resist Wing is Defense, Genius Wing is Special Attack, Clever Wing is Special Defense, and Swift Wing is Speed.) Unlike Vitamins, wings can raise a Pokemon's EVs over 100.
A Pokemon can have up to 510 EVs in all stats combined and a maximum of 255 in each stat.