# Why is informed search more efficient than uninformed search?

Why does informed search more efficiently finds a solution than an uninformed search?

What is a more informed heuristic? Intuitively, it is an heuristic that more rapidly focuses on the promising parts of the search space. Let's denoted by $$h$$ the heuristic function. If $$h(n)=0$$, for all nodes $$n$$, then this is an admissible heuristic, because it always underestimates the distance to the goal (that is, it always returns $$0$$). However, it is a quite uninformed heuristic: either if you are at the start or goal nodes, the estimation is always the same (so you cannot distinguish the start and goal nodes, in terms of estimates). Given two admissible heuristics $$h_1$$ and $$h_2$$, $$h_2$$ is more informed than $$h_1$$ if $$h_1(n) \leq h_2(n)$$, for all nodes $$n$$.