7. EV training - How to -

Lets look at our Tepig again. If we want to give 252 Attack EVs to Tepig you might be thinking that having to battle 252 Patrat is going to be a bit dull. The good news is that there are a large amount of ways we can speed up the entire process.
Hordes.
In Pokémon X & Y, there is a new concept called Horde Battles. These battles bring five Pokémon for you to battle at once, and each of them gives you the standard Effort Value points. They're typically of a low level as well, making them perfect for Effort Training. Hordes may seem rare, but they can be triggered through the use of Honey or the move Sweet Scent, but only when it isn't raining.
Vitamins.
If you head to the Department store on Route 9 in Black & White, and then proceed to the top left corner of the uppermost floor, or in the Pokémon Center in Laverre City in X & Y, you'll find a merchant selling a variety of different vitamins for $9,800 each. They all say they “increase the base stat” of one specific statistic on a Pokémon. Their effects are outlined here.

One vitamin gives 10 EVs in one stat. You can use these items up to 10 times, giving you +100 EVs to the stat of your choosing. So we feed Tepig 10 Protein, and all of a sudden we only have to give 152 EVs via battling, knocking off 100 from the original 252 Patrat we had to battle. But there's more!
Power Items.
There are a number of items in the game you can let your Pokemon hold that increase the amount of EVs they gain from battles. Their effects and location are outlined here.

Macho Brace
Route 15
Doubles the Effort Value Points obtained in battle, but halves the Speed of the holder.

Power Anklet
Battle Maison
Adds four Speed Effort Value Points to all other EV Points gained at the end of a battle, but halves the speed of the holder.

Power Band
Battle Maison
Adds four Special Defense Effort Value Points to all other EV Points gained at the end of a battle, but halves the speed of the holder.

Power Belt
Battle Maison Adds four Defense Effort Value Points to all other EV Points gained at the end of a battle, but halves the speed of the holder.

Power Bracer
Battle Maison
Adds four Attack Effort Value Points to all other EV Points gained at the end of a battle, but halves the speed of the holder.

Power Lens
Battle Maison Adds four Special Attack Effort Value Points to all other EV Points gained at the end of a battle, but halves the speed of the holder. 

Power Weight
Battle Maison
Adds four HP Effort Value Points to all other EV Points gained at the end of a battle, but halves the speed of the holder.

Because we want to train our Tepig in the attack stat, lets give it a Power Bracer to hold. If we go and battle a Patrat, instead of gaining +1 Attack EV from the battle, we're instead gaining +5 EVs from every battle. All of a sudden that daunting figure of 152 Patrat has gone down to just a fraction over 30!

Note as well the “Regardless of the Pokemon fought” aspect of these items; even if we battled a Frillish with Tepig, we'd still be gaining +4 Attack EVs as well as the +1 in Special Defence a Frillish gives, so long as she was holding the Power Bracer.

PokéRus


You may have heard of PokéRus before, but there's a good chance you haven't seen it. It's an extremely rare virus your Pokemon can catch from battling with wild Pokemon, and if you are lucky enough to get it you'll soon find that it is absolutely wonderful for EV training your Pokemon. There are two ways of determining whether or not your Pokemon has been infected with PokéRus.

Pokemon Centre nurses will stop you the next time you go in to heal your Pokemon and tell you about the virus. The other way of finding out if you have the virus is by checking your Pokemon's status page; PokéRus shows up as a little purple box with the letters PKRS in the top right hand corner.
So what use does this have to do with EV training?

PokéRus doubles the amount of EVs you gain from battles and stacks with the power items mentioned above. Lets look at our Tepig once more. Tepig has been fed 10 Protein, meaning she already has 100 Attack EVs in the bank. Next, we've given her the Power Bracer to hold, meaning she gains an additional +4 Attack EVs each battle. Finally lets say we got lucky and have infected Tepig with the virus. Now lets go battle a Patrat (remember, Patrat gives +1 Attack EV).

If you've been doing the maths as you read along, you'll know that with all this Tepig is gaining an outstanding +10 Attack EVs per Patrat battled and defeated, cutting the number we need to fight to max Tepig's attack EVs down to a mere 15.

When are EVs calculated, and can I reset them?

With Black and White the way in which EVs are calculated has been changed. Prior to these games, EVs were calculated each time your Pokémon levelled up. This is no longer the case; they are now calculated after each battle. What this means is that it is now possible for you to EV train a level 100 Pokemon, if you so choose.
We also have the ability to reset EVs if we need to. This is done through using specific berries, one berry will decrease EVs with 10 points.

They're listed here as providing a decrease of 10, however, in Generation IV, the first berry you use will reset the EVs for the stat it effects to 100. This means in order to completely reset a stat we need to use 11 of the specific berry. In Generation V though, you'll need 26 of the berries to completely remove a stat from maximum
Sadly, Black and White have brought with them no way of obtaining these berries aside from through the Dream World.

The berries will be available through the dream world, but will likely be more time consuming to get hold of than they were in previous generations of the games. X & Y allow for you to grow these berries, but you can also completely wipe the EVs by earning a Reset Bag in Super Training, or by purchasing the Perilous Soup in the Juice Shoppe.

Super Training

I have never used Super Training and I believe it takes too long to do EV training. But if you need 4 EVs in one last stat you could use it.

So whats the fastest way to EV train?
Go to the next file/document to see an example.