Best-case performance

The term best-case performance is used in computer science to describe the way an algorithm behaves under optimal conditions. For example, a simple linear search on an array has a worst case performance O(n), when the algorithm has to check every element, and average running time is O(n/2) (see Big O notation), when the item to be found is around the middle of an array, but in best-case running time, the first element that the linear search looks at is the element the algorithm was searching for, and best-case running time is O(1).

It is not practical to base algorithm analysis solely on best-case performance, because most academic and professional industries are more interested in improving worst-case performance and average performance scenarios, as they occur more often than best-case scenarios.