We consider the problem of coalitional manipulation in collective decision making and a probabilistic approach for solving it. We assume that voters have some information about other voters’ preferences from opinion polls held before voting. There are 5 different types of poll information functions. Coalition members are assumed to have identical preferences. We consider the probability that in a randomly chosen preference profile there exists a coalition which has an incentive to manipulate under a given type of poll information. We answer the following questions. How does coalitional manipulability differ from individual? How do different types of poll information affect coalitional manipulability? We answer these questions via both theoretical investigation and computational experiments.