See your list of Pokemon. Assess which ones you have those that you desire to progress and duplicates of. For example, the other has 1 1 CP, plus one has 21 CP and if you might have two Pikachus, move and you'll probably need to retain/evolve the one with 2-1 CP the one with 11 CP. The one with more HP and CP will be stronger in the battlefield. Homepage for more information about pokemon diamond world map right now.