In Tycoon Online, efficiency refers to the minimum productivity level of a building. For example, a building with 50% efficiency and a base production level of 40 will generate between 20 and 40 production points each 10 minutes. The exact value is determined by generating a random number within the given range.
Each type of building has a standard base efficiency. As buildings get older, their efficiency drops due to building deterioration. Some buildings offer a 20% boost in base efficiency as an upgrade option.