Professor Leibowitz, an economist and leading scholar in health policy, focuses on health care and labor economics in her research. Leibowitz has examined the effects of cost-sharing and of managed care on patients' use of the health care system. Her current work focuses on the cost of financing of HIV care and care for children with emotional problems. 

Her research on labor issues has focused on maternity leave and child care issues, including the effect of maternity leave legislation on the participation of new mothers in the labor force and examining the correlation between the amount of time parents spend with young children and the children’s tested IQ, academic achievement and income. 

A member of the Los Angeles County Task Force on Access to Health Care, Leibowitz has testified on health care financing issues before committees of the California Assembly and Congress. During her 18-year career at RAND Corporation, she served as director of the Center for the Study of Employee Benefits and as associate director of the RAND Health Sciences Program.