One explanation for this is that the more implicit feedback information generated, the more representative terms can be obtained, and thus, the iterative algorithm can perform better, leading to more precise search results.
(J. Pitkow et al., 2002) to the best of our knowledge, how to exploit these two types of implicit feedback in a unified way, which not only brings collaboration between query expansion and result re-ranking but also makes the whole system more concise, has so far not been well studied in the previous work.