Help please!!! I am trying to ev train my pokemon in pokemon white but it isnt working?

I want to higher my pokemons attack stats so i went to route one to fight patrat / lillipup becuase they give you +1 attack ev. I know that to gain one attack point stat you need to beat four of them. And so i beat four of them but nothing happens. I really want to figure out how to do this so i can ev train all of my pokemon. Anyones help is greatly appreciated.