Declining labour market dynamism of workers results in an increasing wedge between their earnings and their marginal product as they age. This wedge and the demographic shift in the earnings shares of older workers can account for 59% of the decline in labor’s share of earnings in the United States.
We estimate an aggregate elasticity of substitution between capital and labor near or below one, which implies that capital deepening cannot explain the global decline in labor's share. Our methodology derives from transition paths in the neo-classical growth model.
