In addition to his work at UC Berkeley he also served from 1990 to 1998 as an adjunct professor of epidemiology at the University of Michigan and since 2005 as a professor of biostatistics at the Johns Hopkins University in Baltimore.
Selain karyanya di UC Berkeley ia juga menjabat dari tahun 1990 hingga 1998 sebagai asisten profesor epidemiologi di University of Michigan dan sejak tahun 2005 sebagai seorang profesor biostatistik di Johns Hopkins University di Baltimore.