Measuring Upward Mobility
提出并衡量收入或财富的向上流动性，核心是增长进步性公理，该公理要求将瞬时增长率从富人转移给穷人会提高向上流动性，并据此构建了一个不依赖面板数据的向上流动性指数，适用于数据匮乏的环境。
We conceptualize and measure upward mobility over income or wealth. At the core of our exercise is the Growth Progressivity Axiom: transfers of instantaneous growth rates from relatively rich to poor individuals increases upward mobility. This axiom, along with mild auxiliary restrictions, identifies an “upward mobility kernel” with a single free parameter, in which mobility is linear in individual growth rates, with geometrically declining weights on baseline incomes. We extend this kernel to trajectories over intervals. The analysis delivers an upward mobility index that does not rely on panel data. That significantly expands our analytical scope to data-poor settings.