Helpful Guide to Individual Values and Effort Values

[Deneves]

Individual Values or IVs are hidden numbers that are added to each stat: Hit Points (HP), Attack, Defense, Special Attack, Special Defense and Speed. These numbers range from 0-31 for each stat and will gradually add to that particular stat until the pokémon reaches level 100.
For instance if a pokémon has a 24 IV in a particular stat, at level 25, it will be 6 stat points higher than its base stat solely due to its IV. At level 50, it will be 12 points above its base stat. At level 75, it will be 18 points above its base stat and at level 100 you will find all 24 points will show up in its stat
Although these numbers are hidden, the effects on each stat are not. By charting the increase in stat values you can determine what these IVs are by use of a complicated mathematical equation or by using an IV calculator.


Effort Values or EVs are gradually added to each stat as a reward for pokémon battling experience. Each pokémon you battle either in the wild or by battling a trainer or Gym leader in the game has an assigned Effort Value. Unlike experience points that are divided among all the pokémon in the battle and those with Experience Share, all the pokémon involved receive full share in EVs.
These Effort Values range in each stat from 0-255. The maximum total Effort Values counted towards each pokémon is 510 for all stats combined. For every 4 EVs in one particular stat, 1 point is added to that stat. Since you need 4 EVs to add one stat point, the maximum EVs that can be used is 252 for each stat equal to 63 stat points. Similar to IVs these will be distributed as the pokemon grows in level until it reaches level 100.

[Deneves]

While IVs are totally random in wild pokémon, when it comes to hatchlings, there is some influence on IVs from the parents. The IVs are created at random for each egg by a Random Number Generator (RNG), then
a random IV is passed down from either parent. A second random IV, except a HP IV, is passed down from the other parent. Finally a 3rd random IV, except a HP or Defense IV, is passed down from the parents making a total of 3 IVs that can be passed down from the parents.


There are many helpful threads to help you better understand IVs

This thread has a reference sheet to match a pokémon characteristics with possible IV values and discusses probabilities of inheriting a parents IV values

IV Reference Sheet

This thread discusses how to do IV battling to determine a pokémon’s IVs.

IV Battling

This thread is where you can request IV battles with other members

Battles via DS- IV Battles

This thread is used to post experiences with IVs and show off some of your breeding accomplishments

Individual Value Services

[Deneves]

Another new feature in Platinum is a man standing by the PC in the Battle Tower that can assess your pokemon's IVs

First he will give you an assessment of its total IVs for all six stats:

This Pokémon's potential is decent all around. Between 0 and 90
This Pokémon's potential is above average overall. Between 91 and 120
This Pokémon has relatively superior potential overall Between 121 and 150
This Pokémon has outstanding potential overall. Between 151 and 186

Then he will give an assessment to the stat with the highest IV:

It's rather decent in that regard - 0-15
It's very good in that regard - 16-25
It's fantastic in that regard - 26-30
It can't be better in that regard - 31
I have found that if you have two stats that are tied that he will sometimes switch the stat he is referring to.

While these do not give you the total picture of a pokémon's IVs, it can be helpful with very low level pokémon. If you are going through a batch of newly hatched pokémon, it may weed some out without doing time consuming IV battles.
Also there is a Regigigas at level 1 that can be caught in Platinum. Doing an IV battle means that you must first save the game. Many players prefer to soft-reset for nature and IVs and the IV checker can give you a gauge of its IVs without saving.

[Deneves]

Effort Values are not involved in breeding and are up to the trainers discretion on where they would like to add those extra stat points. So they aren't in the domain of the farmer, but in those that adopt their hatchlings.

There are several great threads that help in this area:

Effort Values FTW is a great overview of Effort Values

Which Pokemon Give Which EVs gives you the essential information of knowing what and where to look for desired EV training along with links to EV checklists

EV Training Plans gives you ideas on fastrack training to get desired EVs

Fifth Generation EVs will help you find the desired EVS of wild pokemon if you are starting out in Black or White

[Deneves]

Power Items Breeding in HeartGold and SoulSilver

A new twist to IV breeding is added in HeartGold and SoulSilver. If a Power Item is being held by a pokémon in the daycare the corresponding IV will be passed down to offspring. If both parents hold Power Items, only one IV is guaranteed to be passed down to the offspring. I believe nature is more crucial than IVs and you will want to have your female hold an everstone in your final breeding to increase the likelihood of a beneficial nature.

Power Weight - passes down the HP stat
Power Bracer - passes down the Attack stat
Power Belt - passes down the Defense stat
Power Lens - passes down the Special Attack stat
Power Band - passes down the Special Defense stat
Power Anklet - passes down the Speed stat

Keep in mind the odds without these power items of passing down an IV to the offspring are:
HP: 8.02% chance of being inherited
Attack: 19.55% chance of being inherited
Def: 13.78% chance of being inherited
SpAtk: 19.55% chance of being inherited
SpDef: 19.55% chance of being inherited
Speed: 19.55% chance of being inherited

[Deneves]

Unlike previous generations where the Hp and Defense IVs were filled first, all IVs have an equal chance of passing down to the offspring. Three IVs are always passed down and without the use of power items the odds of passing IVs to offspring are:

25% chance of inheriting 3 of Parent A's IVs and 0 of Parent B's IVs.
25% chance of inheriting 2 of Parent A's IVs and 1 of Parent B's IVs.
25% chance of inheriting 1 of Parent A's IVs and 2 of Parent B's IVs.
25% chance of inheriting 0 of Parent A's IVs and 3 of Parent B's IVs.

Of course a power item will assure at least one of that parents IV being passed down.
With half of the IVs coming from the parents it is more than ever important to have parents with superior IVs.

Destiny Knot has a new breeding quality now. If one of the parents are holding it while breeding, five IVs will be passed down instead of three. These are picked at random between the parents. All five may come from one parent.
Breeding two parents with 6 perfect IVs will produce offspring with at least 5 IVs and a 1 in 32 chance of a perfect offspring.
Breeding two parents with the same 5 IVs has a 19.75% chance of producing offspring with those same IVs.