Professor Ong has done research on the labor market status of minorities and immigrants, displaced high-tech workers, work and welfare and transportation access. He is currently engaged in several projects, including studies on the effects of neighborhood economies on welfare and work, community economic development in minority communities, and the labor market for healthcare workers. Previous research projects have included studies of the impact of defense cuts on California's once-dominant aerospace industry, the impact of immigration on the employment status of young African Americans, and the influence of car ownership and subsidized housing on welfare usage. He was co-author of a widely reported 1994 study on Asian Pacific Americans, which challenged the popular stereotype of Asians as the country's "model minority" by showing they are just as likely as other groups to be impoverished. Dr. Ong has served as an advisor to the U.S. Bureau of the Census, and to the California Department of Social Services and the state Department of Employment Development, as well as the Wellness Foundation and the South Coast Air Quality Management District.