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The iconic SPECIAL stats make an appearance once again withFallout Shelterbut in a slightly different form. Unlike inotherFalloutgameswhere they are linked to either skills or perks, SPECIALs grant small passive bonuses to dwellers while producing resources, exploring, and questing inFallout Shelter.
For those new to theFalloutfranchise, SPECIAL is an acronym that stands for Strength, Perception, Endurance, Charisma, Intelligence, Agility, and Luck. Each one of those attributes plays a large role in leveling up your character, or in the case ofFallout Shelter, your dwellers.

Hence, knowing what each SPECIAL does determines how efficiently you run your vault. Dwellers having a high SPECIAL will perform better in a room than others. Some also gain better combat bonuses or passives to find more loot. You cannot randomly assign dwellers on a whim. You have to take into account their SPECIALs. Here’s what there is to know about each SPECIAL inFallout Shelter.
Room and Vault Effects

Improved in
Improves production in Power Generators and Nuclear Reactors.

None.
Weight Room.
Strength helps increase the rate of power production for a vault inFallout Shelter. Your dwellers take less time to produce more power to keep the lights running. Strength also increases the crafting speed of some weapons in the Weapon Workshop.
While exploring the wasteland, a higher Strength improves the chance of opening lockers and doors for legendary loot inFallout Shelter.

Improves production in Water Treatments and Water Purifications.
Slows down the critical hit meter.
Armory.
Perception helps increase the rate of water production for a vault, but its best use is discovering new locations like abandoned buildings in the wasteland. While there is no guarantee that a new location will have legendary loot, you may still find lots of resources to craft weapons and armor.
In addition, a higher Perception slows down the critical indicator to let you score powerful hits with ease. It is one of thebetter combat stats to have inFallout Shelter.

Fitness Room.
Endurance is another important SPECIAL stat that improves survivability inFallout Shelter. It lets dwellers gain additional health points when leveling up. Do note that the health bonuses do not trigger retroactively. Hence, a low-level dweller with maxed Endurance will have higher maximum health points than a high-level dweller with low Endurance.
In addition, dwellers stop taking radiation damage while questing after maxing Endurance. Considering how high-level quests always do radiation damage, it pays to level up Endurance for all your dwellers from the start.

Level 1 dwellers with 10 Endurance can achieve the maximum health possible inFallout Shelterby equippinglegendary heavy wasteland gear.
Endurance also improves the rate of food and water production in the Nuka-Cola Bottler Rooms. Dwellers with high Endurance can be assigned to the Storage Room to increase their happiness. However, that will not increase your storage capacity.

Lounge.
Charisma is the only SPECIAL stat that increases your vault population inFallout Shelter. It helpsdeliver more babiesby reducing pregnancy timers and sends out good words through the radio to attract friendly wastelanders. Charisma also increases the likelihood ofmeeting legendary wastelanders while exploringand convincing them to come to the vault.
Fallout Sheltersets a population cap at 200. You cannot have more dwellers than that. However, you do not necessarily have to remove rooms like Radio Stations and Living Quarters after hitting the cap. Dwellers die of old age, so you will always need to replace them with new blood.

Classroom.
Intelligence is primarily used to reduce the time taken to produce Stimpaks and RadAways. These two items are essential in surviving the wasteland inFallout Shelter. Giving dwellers stacks of Stimpaks and RadAways allows them to stay for longer periods in the wasteland. The more days they spend exploring, the more loot they will bring back. Intelligence also comes in handy if you want to level up dwellers fast. Investing a few points in Intelligence grants them bonus experience points for completing tasks in the vault or the wasteland.
Athletics Room.
Agility improves the efficiency of producing food in the vault. Its primary use, though, is training dwellers to do more damage per second with weapons. The high fire rate is only applicable to guns, and is an important SPECIAL stat while exploring the wasteland or when questing. Dwellers with high Agility canmake short work of Deathclaws inFallout Shelter.
Another thing that makes Agility useful is its ability to let you escape hopeless battles. You cannot afford to lose high-level dwellers! They eat a ton of resources before being able to complete quests in the wasteland. Hence, use Agility to flee the battlefield when necessary.
Game Room.
Luck is a late-game SPECIAL stat inFallout Shelter. While a higher Luck doesgive more daily caps, the amount pales against how much loot dwellers can bring back to the vault from the wasteland. A high-level dweller can stay for weeks in the wasteland without dying. Sending out the same dweller with maxed-out Luck is guaranteed to bring back enough caps to fill your coffers. Another advantage of a high enough Luck rating is a high success rate for rushing production. In an emergency, you’re able to rush rooms multiple times without setting off a hazard. This comes in handy when your vault is being raided by enemies.