IV and EV training have been a mainstay of the Pokémon games for most of the series' existence, but Pokémon Legends: Arceus breaks that tradition. Featuring neither IVs or EVs, Legends: Arceus has a new method of determining a Pokémon's stat growths. This is not a change for the sake of changing, but rather a new gimmick that fits well with the game's design.
IVs and EVs stand for Individual Values and Effort Values. IVs are internal modifications to a Pokémon's stats that are unique to each Pokémon. EVs are cumulative modifiers that rise depending on a Pokémon's battle history. For example, defeating a Geodude will offer Defense EVs, and a Machop will offer Attack EVs. A stat with high IVs and EVs will grow much more than one with low IVs and EVs. Normally IVs and EVs are hidden, but some recent additions such as Sword & Shield's IV Checker can reveal them to the player. IVs can even be ed down through breeding if one of the parent Pokémon is holding a Destiny Knot. With so many details, IV and EV training and breeding have been a major part of the competitive scene in Pokémon.
As Legends: Arceus has changed so many other things from the series norm, this method of determining stats has changed as well. IVs and EVs do not exist in Pokémon Legends: Arceus at all. Instead, they have both been replaced with a new stat known as Effort Levels. Much like IVs and EVs, Effort Levels help to raise a Pokémon's stats - and higher Effort Levels for a specific stat yield higher results. With Legends: Arceus upgrading many previously pathetic Pokémon, the extra stats are certainly appreciated. In addition, Effort Levels are clearly shown and easy to check, unlike IVs and EVs which are frequently hidden and harder for the player to gauge.
Effort Levels Replace EVs and IVs in Pokémon Legends: Arceus
Rather than inborn IVs and battle-based EVs, Legends: Arceus has a completely different method of raising Effort Levels. By using Grit items, the player can raise the Effort Levels of a selected stat. Reaching higher Effort Levels requires more potent Grit items. For example, a Pokémon with no Effort levels in a stat can raise it with Grit Dust, but a rarer Grit Rock is needed to maximize a stat's effort values. Raising Effort Levels is quite easy to do, only requiring the player to gather the correct Grit items. Even though Legends: Arceus is not a normal Pokémon game, managing Pokémon stats is still important.
As for the reason why IVs and EVs have been replaced with effort values, there is a simple explanation. IVs and EVs are mechanics centered around breeding and training. However, in Legends: Arceus, there is no breeding mechanic, and proper Pokémon training is still extremely niche. It's likely that IVs and EVs were discovered later in the series' timeline, meaning that they would not be known in the time of Hisui. As a result, the more simple Effort Levels system takes their place. Effort Levels are easy to calculate and advance through items that can be found easily, so they make sense as a more low-tech alternative to EVs and IVs. Similar to Legends: Arceus' Linking Cord, Effort Levels are a great innovation for the game.
Effort Values are another mechanic that differentiates Legends: Arceus from the rest of the series, but it fits well into the game. It makes training Pokémon much easier than before and makes sense in the setting. Pokémon Legends: Arceus has a lot of innovations for the series, and Effort Levels are one of the better ones.
