Stats and Training

Stats and Training by Akis1988

Here you can find all the information you need to understand the games' mechanics that have to do with the Pokémon's stats, growth and training. There are two sections; the first explains everything that applies in Ruby, Sapphire, Fire Red, Leaf Green, Emerald and Colosseum and the second explains everything that applies in Gold, Silver, Crystal, Stadium and Stadium 2 since things are different between those two generations.

* Advanced Generation2 (Ruby, Sapphire, Fire Red, Leaf Green, Emerald, Colosseum)
* Metal Generation3 (Gold, Silver, Crystal, Stadium, Stadium 2)

Related Links

* Base ability values, Base Experience, Effort Points4
* Max ability values5
* Stat Calculator6
* IV Calculator7
* Natures8

Advanced Generation
Visible stats

Each Pokémon has six visible stats: Hit Points (HP), Attack, Defence, Special Attack (Sp. Atk), Special Defence (Sp. Def) and Speed. Those stats show the Pokémon's strenght. Hit Points represents the amount of damage a Pokémon can get, when its Hit Points reach zero, the Pokémon faints. Attack represents the strenght of a Pokémon when using physical attacks (Normal, Fighting, Poison, Ground, Rock, Bug, Flying, Ghost, Steel) while Special Attack is the same but for special attacks (Psychic, Water, Fire, Ice, Grass, Electric, Dragon, Dark). Defence represents the strenght of a Pokémon when suffering physical attacks while Special is the same but for special attacks. Speed represents the the speed of a Pokémon in battle and in most cases determines who attacks first. Continue reading for more about what influences their growth. There are also two in-battle stats, Accuracy and Evasion, that are only affected by moves and abilities and cannot be raised by training a Pokémon.
Level

Pokémon have levels that show how much they have been trained (not how well though). As your Pokémon gathers experience, its level will rise. The shortest level you can find a Pokémon at is 2. Pokémon that come out of eggs are level 5 and the maximum level a Pokémon can reach is 100. Each time a Pokémon levels up, it gets a small stat boost. Except from battling, you can also use a Rare Candy to level up a Pokémon by 1. However using many Rare Candies to level up a Pokémon is not that wise, because Rare Candies do not provide Effort Points. Finally, if for some reason your Pokémon has reached level 100 and doesn't have an Effort Ribbon, make it have a lot of battles and then Deposit it into the PC and Withdraw it, you shall notice a small boost in some stats; that's called "The Box Trick".
Base Stats

Base Stats, or Base Statistics or Base Values are the standard, basic statistics values that determine a Pokémon species strength. Each Pokémon species has its own, different set of Base Stats. Also, the higher the Base Stat, the higher the final stat for that Pokémon will be. For example, Pikachu's Base Stat for Attack is 55 and its Special Attack Base Stat is 50, therefore an untrained Pikachu will almost always have an Attack higher than its Special Attack. Base Stats also explain the potential of different species. For example, a Gardevoir has a Special Attack Base Stat of 125, while Metagross has a Base Stat of 95 for its Special Attack. That means that a Gardevoir will be more effective when using special attacks (like Psychic) than Metagross.
Individual Values

Individual Values, IVs for short (or Deter Values and DVs) are in simple words the "genes" of a Pokémon. An IV in the Advanced Generation have 32 possible values; 0 is the minimum IV a stat can have and 31 is the maximum. The IVs are generated randomly upon the encountering a Pokémon or the creation of an egg (not the hatch). A Pokémon's IVs are fixed and there is no way to modify them. IVs are Pokémon dependant and not species dependant. For example you can have a Pikachu with an Attack IV of 28, a Pikachu with an Attack IV of 5, a Bulbasaur with an Attack IV of 5 and so on. IVs are really important since they can make the difference between victory and loss in a battle. For example, a Pikachu at level 100 with an IV of 28, neutral nature and 253 Effort Points in Attack, will have an Attack of 206, whilst a Pikachu at level 100 with an IV of 5, neutral nature and 253 Effort Points in Attack will have an Attack of only 183. This means there's a difference of 23 points in Attack which can be critical. However, getting a Pokémon with an IV of 31 in one or more stats is extremely difficult. You have 1 chance in 32 to get a an IV of 31 in one stat, 1 in 1.024 to get a max IV in two stats and 1 chance in 1.073.741.824 to find a Pokémon with max IV in all 6 stats. Obviously, the best way to get a Pokémon with good IVs is making eggs, lots of eggs unless the Pokémon you want is genderless or a legendary; in that case your only option is to try and find the best.
Note: Calculating IVs in low levels may cause faulse results because the game hides the decimals from the Pokémon's stats by rounding them down.
Formula for calculating HP IV:
IV = (((HP - level - 10) * 100) / level) - EP/4 - (base stat * 2)
Formula for calculating stat IVs:
IV = (((stat / nature) - 5) * 100 / level) - EP/4 - (base stat * 2)
Effort Values, Vitamins and Pokérus

Effort Points or Battle Experience and Effort Values, EPs and EPVs accordingly, are the ones that make the difference between untrained and trained Pokémon. All Pokémon have six Effort Values: Hit Points, Attack, Defence, Special Attack, Special Defence, Speed and when they are first obtained their Effort Values are zero. When a Pokémon defeats an enemy Pokémon in a battle, it gets a certain amount of Effort Points for a certain stat, depending on the enemy Pokémon's species (defeating a Pikachu for example provides 2 Effort Points in Speed). Exp.Share makes Pokémon that hold it not only share experience points with the battlers but also gives them exactly the same number of Effort Points. A Pokémon can only get 510 Effort Points, and the maximum Effort Points a stat can get (or the maximum an Effort Value can reach) is 255 which means only two stats can reach their maximum. Therefore it is impossible to reach the maximum potential of a Pokémon. However, since the formula that calculates the stats of a Pokémon uses an "Effort Level", which equals with (Effort Points)/4 rounded down and since "Effort Level's" maximum is 63 (255/4 rounded down), having 252, or more Effort Points in a stat is exactly the same. Obviously 6 Effort Points don't bonus up anything unless you use the to raise another stat's "Effort Level" by 1 (6/4 rounded down) but that is a very small change and practically effectless. Finally, when a Pokémon gains all 510 Effort Points it can get, you can go to Slateport and give it an Effort Ribbon to show that it is trained.

Vitamins are items that provide Effort Points when given to a Pokémon. Protein, Iron, Carbos, Zinc, Calcium and HP Up are all vitamins, and each of them boosts a certain stat. Protein boosts a Pokémon's Attack, Iron boosts its Defence, Carbos boosts its Speed, Zinc boosts its Special Defence, Calcium boosts its Special Attack and HP Up boosts its Hit Points. They provide 10 Effort Points in the appropriate stat. However a Pokémon can only eat 10 of each vitamin. A Pokémon can eat up to 51 vitamins, getting 510 Effort Points in total.

In Emerald version, thePomeg9, Kelpsy10, Qualot11, Hondew12, Grepa13 and Tamato14 berries, act like anti-vitamins for HP, Attack, Defense, Special Attack, Special Defense and Speed, removing 10 Effort Points each and allowing the re-training of the Pokémon.

Pokérus (Pokémon Virus) is a special condition that was firstly introduced in Gold/Silver. A Pokémon can get infected with Pokérus from either a wild (1 chance out of 21845) or another infected Pokémon. If you visit a Pokémon Center and one of your Pokémon is infected, then Nurse Joy will inform you that they have got Pokérus. A Pokémon that has Pokérus or even a cured one (Pokérus leaves after a short time if you leave the infected Pokémon outside the PC) gains double the amount of Effort Points it gets from battles (for example if it defeats a Pikachu, it will get 4 Speed Effort Points since Pikachu provides 2 Speed Effort Points). That makes Pokérus a good virus and a really usefull tool when training. Macho Brace also gives the same effect with Pokérus to the Pokémon that holds it, so if a Pokémon is infected with Pokérus and holds Macho Brace it will get 4 times the Effort Points it would normally get. Pokérus easily infects other Pokémon in your team if one of them is infected by just having battles. However, since it lasts very little, you may want to keep a Pokémon infected with it in the PC, so it doesn't get cured.
Nature

A Pokémon's nature, often called Personality, determines in which stat a Pokémon will have a small bonus (10%) and in which it will have a small reduction (10%). There are 25 natures in total. Five of them are neutral, meaning they have give neither bonuses nor reductions to stats. The rest boost a certain stat while reducing another. Selecting the appropriate Nature for your Pokémon is critical since some stats should be raised more than some others.
Metal Generation
Visible stats

Each Pokémon has six visible stats: Hit Points (HP), Attack, Defence, Special Attack (Sp. Atk), Special Defence (Sp. Def) and Speed. Those stats show the Pokémon's strenght. Hit Points represents the amount of damage a Pokémon can get, when its Hit Points reach zero, the Pokémon faints. Attack represents the strenght of a Pokémon when using physical attacks (Normal, Fighting, Poison, Ground, Rock, Bug, Flying, Ghost, Steel) while Special Attack is the same but for special attacks (Psychic, Water, Fire, Ice, Grass, Electric, Dragon, Dark). Defence represents the strenght of a Pokémon when suffering physical attacks while Special is the same but for special attacks. Speed represents the the speed of a Pokémon in battle and in most cases determines who attacks first. Continue reading for more about what influences their growth. There are also two in-battle stats, Accuracy and Evasion, that are only affected by moves and abilities and cannot be raised by training a Pokémon.
Level

Pokémon have levels that show how much they have been trained (not how well though). As your Pokémon gathers experience, its level will rise. The shortest level you can find a Pokémon at is 2. Pokémon that come out of eggs are level 5 and the maximum level a Pokémon can reach is 100. Each time a Pokémon levels up, it gets a small stat boost. Except from battling, you can also use a Rare Candy to level up a Pokémon by 1. However using many Rare Candies to level up a Pokémon is not that wise, because Rare Candies do not provide Effort Points. Finally, if for some reason your Pokémon has reached level 100 and doesn't have all the Effort Points it could get, make it have a lot of battles and then Deposit it into the PC and Withdraw it, you shall notice a small boost in some stats; that's called "The Box Trick".
Base Stats

Base Stats, or Base Statistics or Base Values are the standard, basic statistics values that determine a Pokémon species strength. Each Pokémon species has its own, different set of Base Stats. Also, the higher the Base Stat, the higher the final stat for that Pokémon will be. For example, Pikachu's Base Stat for Attack is 55 and its Special Attack Base Stat is 50, therefore an untrained Pikachu will almost always have an Attack higher than its Special Attack. Base Stats also explain the potential of different species. For example, a Celebi has a Special Attack Base Stat of 100, while Bulbasaur has a Base Stat of 65 for its Special Attack. That means that a Celebi will be more effective when using special attacks (like Psychic) than Bulbasaur.
Individual Values

Individual Values, IVs for short (or Deter Values and DVs) are in simple words the "genes" of a Pokémon. An IV in the G/S Generation have 16 possible values; 0 is the minimum IV a stat can have and 15 is the maximum. The IVs are generated randomly upon the encountering a Pokémon or the creation of an egg (not the hatch). A Pokémon's IVs are fixed and there is no way to modify them. IVs are Pokémon dependant and not species dependant. For example you can have a Pikachu with an Attack IV of 5, a Pikachu with an Attack IV of 10, a Bulbasaur with an Attack IV of 5 and so on. IVs are really important since they can make the difference between victory and loss in a battle. However, getting a Pokémon with an IV of 15 in one or more stats is extremely difficult. You have 1 chance in 16 to get a an IV of 15 in one stat (excluding Hit Points IV which isn't random), 1 in 256 to get a max IV in two stats and 1 chance in 65.536 to find a Pokémon with max IV in all 4 (since Sp. ATk and Sp. Def share the same Special IV) stats. Obviously, the best way to get a Pokémon with good IVs is making eggs, lots of eggs unless the Pokémon you want is genderless or a legendary; in that case your only option is to try and find the best.
Note: Calculating IVs in low levels may cause faulse results because the game hides the decimals from the Pokémon's stats by rounding them down.
Formula for calculating stat IVs:
IV = ((stat - 5)*50 / level) - Effort Level - base stat
Formula for calculating HP IV:
IV = ((HP - 10)*50 / level) - Effort Level - base stat - 50
Steps for calculating HP IV by using other IVs:
Turn each IV (Attack, Defence, Speed, Special) into a binary number (4 digit) using the conversion table below. Then take the last digit of each binary result and form the HP IV.

* 0 = 0000
* 1 = 0001
* 2 = 0010
* 3 = 0011
* 4 = 0100
* 5 = 0101
* 6 = 0110
* 7 = 0111
* 8 = 1000
* 9 = 1001
* 10 = 1010
* 11 = 1011
* 12 = 1100
* 13 = 1101
* 14 = 1110
* 15 = 1111

Effort Values, Vitamins and Pokérus

Effort Points or Battle Experience and Effort Values, EVs and EPs accordingly, are the ones that make the difference between untrained and trained Pokémon. All Pokémon have six Effort Values: Hit Points, Attack, Defence, Special Attack, Special Defence, Speed and when they are first obtained their Effort Values are zero. When a Pokémon defeats an enemy Pokémon in a battle, it gets a certain amount of Effort Points for a certain stat, depending on the enemy Pokémon's species (defeating a Pikachu for example provides some Effort Points in Speed). Exp.Share makes Pokémon that hold it not only share experience points with the battlers but also gives them exactly the same number of Effort Points.
detailed research pending

Vitamins are items that provide Effort Points when given to a Pokémon. Protein, Iron, Carbos, Zinc, Calcium and HP Up are all vitamins, and each of them boosts a certain stat. Protein boosts a Pokémon's Attack, Iron boosts its Defence, Carbos boosts its Speed, Calcium boosts its Special and HP Up boosts its Hit Points. They provide ??? Effort Points in the appropriate stat. However a Pokémon can only eat 10 of each vitamin.
detailed research pending

Pokérus (Pokémon Virus) is a special condition that was firstly introduced in Gold/Silver. A Pokémon can get infected with Pokérus from either a wild or another infected Pokémon. If you visit a Pokémon Center and one of your Pokémon is infected, then Nurse Joy will inform you that they have got strange life forms on them and later Prof. Elm will call you in order to tell you more. A Pokémon that has Pokérus (Pokérus leaves after a short time if you leave the infected Pokémon outside the PC) gains double the amount of Effort Points it gets from battles. That makes Pokérus a good virus and a really usefull tool when training. Pokérus easily infects other Pokémon in your team if one of them is infected by just having battles. However, since it lasts very little, you may want to keep a Pokémon infected with it in the PC, so it doesn't get cured.