2001-2007: Senior Staff Scientist, Fred Hutchinson Cancer Research Center.
2003-2004: Research Associate Professor, Mathematics, North Carolina State University.
1995-2001: Staff Scientist, Fred Hutchinson Cancer Research Center.
1995: Statistical Research Associate, Fred Hutchinson Cancer Research Center.
1993-1995: Postdoctoral Fellow, Department of Biostatistics, University of Washington.
1990-1995 (on leave 9/93-6/95): Assistant Professor, Department of Mathematics, University of Missouri-Rolla.