Since around 1980, fewer Americans than before are doing better than their parents had - that is, more are experiencing downward social and economic mobility in terms of occupational status and income. This trend in downward mobility is occurring amidst high and rising levels of inequality in income, wealth, health, and life expectancy. To better understand the factors that influence social and economic mobility, the Committee on Population and the Committee on National Statistics hosted a workshop on February 14-15, 2022. The proceedings from this workshop identify key priorities for future research and data collection to improve social and economic mobility.