Who is on LinkedIn? Self-selection into professional online networks

We analyze a large data set of fully employed individuals gathered through incentive-compatible surveys to study who joins professional social network sites (SNS) such as LinkedIn. We test the conflicting predictions that a) individuals who are unsatisfied with their career status adversely select into professional SNS in order to reap marginal online network benefits vs. b) high status individuals positively select into these networks because they are more likely to receive invitations to join. Our tests support b) and reject a). Similar estimations for private SNS (e.g., Facebook) reveal that the observed effects are specific to professional SNS and hence not driven by unobserved differences in social capital or the affinity to use social media. We also detect that environments conducive of professional social interactions increase the likelihood to use professional SNS. Controlling for sample selection bias does not qualitatively change the results.