  Ranking problem of web-based rating system has attracted many attentions. A
good ranking algorithm should be robust against spammer attack. Here we
proposed a correlation based reputation algorithm to solve the ranking problem
of such rating systems where user votes some objects with ratings. In this
algorithm, reputation of user is iteratively determined by the correlation
coefficient between his/her rating vector and the corresponding objects'
weighted average rating vector. Comparing with iterative refinement (IR) and
mean score algorithm, results for both artificial and real data indicate that,
the present algorithm shows a higher robustness against spammer attack.
