Mentorship provides an important influence on how scientific researchers develop professionally. Most researchers spend several years training under just one or two graduate and/or postdoctoral mentors, suggesting that this small number of relationships can have large impact on subsequent careers. Mentorship can have both direct intellectual benefits to the trainee through the learning of new skills and concepts and indirect social benefits through engagement with the social network of the mentor. Networks of mentors and trainees can be represented by a directional graph resembling a traditional family tree. This project develops a large database of academic mentorship relationships and tools for analyzing the impact of mentorship on scientific careers. Development of this database addresses the mission of the Science of Science & Innovation Policy program. The data will be made open-access for general use by the public, providing a new resource for studying the dynamics of academic research fields. More generally, the Academic Family Tree represents a successful crowdsourcing project and provides an example for other efforts to engage the public in scientific research projects.<br/><br/>This project uses semantic and graph theoretic analyses to characterize the impact of mentorship networks on professional success and on the evolution of research fields. This project uses crowdsourcing to expand the Academic Family Tree, a public, web-based database of formal mentoring relationships (doctoral and postdoctoral) across all fields of academic research. Researchers in the mentorship database are linked to publication metadata in multiple publication databases and to funding data in the Federal RePORTER database. Semantic and graph theoretic analyses are used to determine what features of the mentorship network influence the subsequent careers of trainees. Focusing on trainees with at least two mentors, these analyses evaluate direct intellectual impact of mentor expertise, measured by latent semantic analysis of publications, and indirect social impact, measured by the similarity of the lineage of the two mentors in the larger academic genealogy. Two measures of trainees' professional success are considered: the number of trainees they themselves mentor and their ability to obtain research funding.