Expert networks are formed by a group of expert-professionals with different specialties to collaboratively resolve specific queries posted to the network. In expert networks, decentralized search, operating purely on each expert's local information without any knowledge of network global structure, represents the most basic and scalable routing mechanism. However, there is still a lack of fundamental understanding of the efficiency of decentralized search. In this regard, we investigate decentralized search by quantifying its performance under a variety of network settings. Our key findings reveal that under certain network conditions, decentralized search can achieve significantly small query routing steps (i.e., between O(log n) and O(log2 n), n: total number of experts in the network). To the best of our knowledge, this is the first work studying fundamental behaviors of decentralized search in expert networks.