1. A computer-implemented method comprising: obtaining keywords from user profiles of a group of users of a social networking system who previously responded to an invitation; extracting a set of keywords from a subject user profile of a subject user of the social networking system; determining a first occurrence of keywords in the set of keywords in a first group of user profiles corresponding to a group of users of the social networking system who responded positively to the invitation; determining a second occurrence of keywords in the set of keywords in a second group of user profiles corresponding to a group of users who responded negatively to the invitation; computing a score for one or more of the keywords in the set of keywords based on a comparison of the first occurrence and the second occurrence; and predicting a response to the invitation by the subject user based on the score for one or more of the keywords.