We've published a very useful guide about Pokemon Evs (Effort Value Training). If you hadn't already, make sure to read it also bookmark it so that you can refer to it when needed.
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Sections:
Introduction
Mathematics
Player Influence
Tricks
Introduction:
Effort Values, or EVs, are points that Pokemon gain over the course of fighting other Pokemon. These points can greatly influence how your Pokemon’s stats grow over the course of them leveling to 100. This is a complex while simple element of the game. Many simply don’t know about EVs but still see the effects of them (such as an Alakazam with a high Attack Stat because all it ever fought were Fighting Types). With the right EVs a powerhouse becomes able to decimate attack or any solid wall Pokemon can then tank hits like no other.
Effort Values are earned solely in conjunction with Experience Points. There is no other way to get them. Think of it as a reward that is underneath the frosting of Experience. This is one of the points where playing Pokemon takes a serious turn away from just fun. Calculators are about to become your friend, or at least the in-game calculator is. Early in the game this practice is simply unfeasible to pull off because of the Poke-dollars needed, the sheer amount of movement required and the raw number of items required. This is useful when you are beginning to battle other human opponents at level 100. You, at this point, have free access of the entire map and decent funds (thanks to the Elite Four and an Amulet Coin).
Mathematics:
Here is where math comes in: Every Pokemon can earn up to 510 EVs total across all its stats. Each stat can only have a maximum of 255 EVs applied to it. Every 4 EV translates to...
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Effort Value Training 101