Abstract: In recent years, the emergence of mobile internet-based crowdfunding has provided a new way for the poor to obtain emergency relieves for medical needs. Despite a number of reported scams, medical crowdfunding as a wholes has made an important social contribution to the society. Public opinions and sentiment highlight two practical issues:Are the resources being directed to the people who need the most? And how can we optimize the crowdfunding? To tackle these questions, we focus on the issue of how the socioeconomic status of help seekers affect their internet fundraising outcomes. We ask three research questions:What is the correlation between the socio-economic status of help seekers and their crowdfunding effectiveness? What are the underlying mechanisms for success? Is there a possible optimization path for crowdfunding? Our data is based on the 1 930 fundraising cases from a large medical crowdfunding platform in China. The study finds significant differences in effectiveness among different socio-economic status groups. Higher SES status correlate with higher donation figures, fundraising target completions, a larger number of donations received and more cross-social media platform reposting. This socio-economic gradient phenomenon contradicts the social expectation of prioritizing help to the most needed in medical crowdfunding. The analysis of mediation effect also shows that the offline interpersonal network plays an important intermediary role. While good case narratives are helpful but they are not the intermediary mechanism that links the family's socio-economic status and crowdfunding effect. Further analysis also finds that when fundraising begins with WeChat friends circles and then moves to public platforms, the impact of socioeconomic gradient seems to reduce its significance.

Key words: medical crowdfunding, health inequality, social capital, cultural capital, mobile internet