Are Social Media more Social than Media? Measuring Ideological Homophily and Segregation on Twitter∗

Social media represent a rapidly growing source of information for citizens around the world. In this paper, we measure the degree of ideological homophily and segregation on social media. In particular, we construct a network based upon links between politically-engaged users and find that the network exhibits previously documented homophily patterns in offline social networks. Likewise, the degree of ideological segregation in the network is similar to that in networks based upon face-to-face interactions, such as friends and co-workers, and is higher than that associated with mass media, such as television and newspapers. ∗Preliminary. Please do not cite or circulate without permission of the authors. We are particularly indebted to Zack Hayat for getting this project off the ground and providing continual advice. We thank seminar participants at Berkeley, CU-Boulder, Michigan State, Stanford and Toronto for their input. Ashwin Balamohan, Max Fowler, Kristopher Kivutha and Somang Nam jointly created the infrastructure to obtain the Twitter data used in this paper. Dylan Moore provided outstanding research assistance. Special thanks to Darko Gavrilovic, the IT consultant at Toronto, who facilitated the data work for this project, and Pooya Saadatpanah for providing computing support. We gratefully acknowledge financial support from the Social Sciences and Humanities Research Council of Canada. †Department of Economics, University of Toronto, [email protected] ‡Department of Economics, Brown University and NBER, [email protected]