Modeling peer and external influence in online social networks: Case of 2013 referendum in Croatia

Abstract

In this paper we estimate the magnitude of peer and external influence on users of an opinion poll which was conducted through a Facebook application. Poll question was related to the referendum on the definition of marriage in Croatia held on 1 st of December 2013. Through the application we collected Facebook friendship relationships, demographics and votes of over ten thousand users, as well as data on online news articles mentioning our application. Our hypothesis is that the engagement of users is driven by two main influences - one coming from within the network (peer or endogenous influence) and other coming from outside of the network (external or exogenous influence). The question is whether we can infer magnitude of these two influences using only the Facebook friendship network between users and the times of their voting. We propose a method for estimation of these two influences and demonstrate its validity on both simulated and actual data.