Grinnell College, Professor of Mathematics, present.
Grinnell College, Associate Professor of Mathematics, 1989-2000
Grinnell College, Assistant Professor of Mathematics, 1983-1989
Visiting scholar at Carleton College and Saint Olaf College, 2003-04.
Visiting Associate Professor, Mount Holyoke College, 1997-98.
Eastman Kodak Company, Management Services Division, Applied Statistics Unit, analyst, 1985-1986 (sabbatical)
Grinnell College, Lecturer in Mathematics and Co-coordinator of Computer Studies, 1980-1983
University of Iowa, graduate student, 1979-1980
Marietta College, Assistant Professor of Mathematics, 1976-1979.
Dartmouth College, graduate student, 1971-1976.
Nova High School (Fort Lauderdale, Florida), mathematics teacher, 1969-1971.