i am a principal research scientist at microsoft research in new york city, where my work in the area of computational social science involves applications of statistics and machine learning to large-scale social data. i am also an adjunct assistant professor in columbia university's applied math department and i run the microsoft research data science summer school to promote diversity in computer science. i was previously a member of the social dynamics group at yahoo! research. i received my ph.d. from columbia university's physics department. see my curriculum vitae for more information.