Do Power Items actually reduce Speed EVs?

Question

So I heard EV training is much faster when the Pokemon that is being EV trained holds a Power Item e.g Power Bracer, Weight, etc.

But I am worried about their drawback which is the fact that Speed gets reduced. But in terms of EVs, if the Pokemon I am training doesn't have any speed EVs on it, does the speed stat still get reduced?

Answer 1

The drawback of a power item is temporary, and does not permanently affect your stats. The speed is reduced to half, only as long as the pokemon holds the item. After EV training, you can take the power item back from the pokemon and it will no longer have the speed reduction penalty.(And no it does not affect speed IVs either)

Answer 2

The general idea how to EV train is the following:

• Give the Pokemon you want to train a power item
• Have a strong Pokemon with an all-opponents attack (i.e. Heat Wave for Charizard, or something like Earthquake or Surf) on the first spot
• Have a Pokemon with Sweet Scent in your party.
• Enable Exp. Share
• Go to a location with the hordes (find those locations from this answer)
• Use Sweet Scent, kill the horde with your Strong Pokemon in one hit
• By the Exp. Share your targeted EV-training Pokemon gets experience, and therefor EVs. The power items and Pokerus affects the amount of EVs gained.

So your EV trained Pokemon is never in battle. Therefor the reduced stat is not a problem at all. The EVs of speed are not reduced by using a power item, which probably is the source of your confusion.

I use the above method to EV train my Pokemon, and it is done in less then half an hour, probably less.