Unlike previous Mainstream Pokemon Games, the system for Pokemon Stats has been changed significantly. Natures (which boost and decrease certain Pokemon Stats) and Individual Values (which influence the overall potential for each Pokemon Stat) still exist, but Effort Values (EVs) no longer do. Instead, EVs have been replaced by what are called Awakening Values (AVs). Each of your Pokemon will gain one random Awakening Value each time they level up, but they can gain even more with the use of Pokemon Candy.
Awakening Values work differently than that of Effort Values in that you now use Pokemon Candy to raise a Pokemon's Stats, rather than having to defeat certain Pokemon to gain Effort Values in order to do the same. Pokemon Candy also increases a Pokemon's Awakening Values by one regardless of its level and at the time when said Pokemon Candy is used on a Pokemon, instead of where Efforts Values you would need four EVs to raise a Pokemon's Stats by the value of one and not being seen in a Pokemon's Stats until said Pokemon reaches Level 100. Furthermore, you can have up to 200 Awakening Values per stat for each of your Pokemon, meaning your Pokemon can be much stronger than before.
On top of using Pokemon Candy to improve a Pokemon's Awakening Values and thus their Stats, Happiness also plays a key role in a Pokemon's Stats. Unlike past Pokemon Games, Happiness would have no value in regards to a Pokemon's Stats, but now, that has all changed. You see, the happier your Pokemon are with your trainer, the more their stats will be boosted. Should a Pokemon have Maximum Happiness, its stat points will be increased further by ten percent! This means that even though Pokemon can now be much stronger than in the past due to Awakening Values and Pokemon Candy, they can reach even stronger levels than that!