Our software update is now concluded. You will need to reset your password to log in. In order to do this, you will have to click "Log in" in the top right corner and then "Forgot your password?".
Welcome to PokéCommunity! Register now and join one of the best fan communities on the 'net to talk Pokémon and more! We are not affiliated with The Pokémon Company or Nintendo.
It affects your stat boost when you level up depending on when you train it. If you wait to Level 90 to EV train a Pokemon and finish it before go up to 91, you'll notice a huge increase in the stat that you are EV training in.
On the other hand, if you are EV training at a lower level like Level 20, the stat boost won't be as noticeable but you will eventually gain the rest of the stat boost as your Pokemon levels up.