Barrel theory: If the length of the wooden boards that make up a barrel is uneven, then the water capacity of the barrel does not depend on the longest wooden board, but on the shortest wooden board.
The bucket effect means that if a bucket is to be filled with water, every board must be flush and intact. If a board in the bucket is uneven or there is a hole under a board, the bucket can't be filled with water. How much water a bucket can hold depends not on the longest board, but on the shortest board. It can also be called short board effect. No matter how high a bucket is, the height of the water it holds depends on the lowest board.
Also known as Cannikin Law or barrel effect, the short board management barrel theory, the so-called barrel theory is the barrel law. Its core content is that the amount of water in a bucket does not depend on the tallest piece of wood on the bucket wall, but only on the shortest piece on the bucket wall. According to this core content, the "bucket theory" has two inferences: first, the bucket can only be filled with water if the wooden boards on the bucket wall are high enough. Secondly, as long as one piece in this bucket is not high enough, the water in the bucket will not be full.