[Excerpt] As the large baby boomer generation retires, the workforce will lose much of their knowledge and experience. Encouraging phased retirement, in which older workers reduce their work hours with their current employer to transition into retirement, has been cited by retirement experts as one way to mitigate this loss. GAO was asked to review the work patterns of older Americans and phased retirement programs. In this report, GAO examines (1) recent trends in the labor force participation of older workers, (2) the extent to which employers have adopted phased retirement programs and what type of employers offer them, and (3) what challenges and benefits, if any, exist in designing and operating phased retirement programs. GAO analyzed data from two nationally representative surveys, the Health and Retirement Study (2004-2014) and the Current Population Survey (2005-2016); reviewed relevant federal laws and regulations; conducted a literature review; and interviewed 16 experts on retirement and 9 employers who offer or considered offering phased retirement programs. While phased retirement programs exist in both the private sector and government, this report focuses on private sector programs.