标题： 远离平衡：美国财富再分配 显示英文标题

标题： Far from equilibrium: Wealth reallocation in the United States

摘要： 研究财富不平等的文献通常假设观察到的财富分布反映了处于平衡状态的系统。 这一约束很少在实证中进行检验。 我们引入了一个简单的模型，该模型允许平衡状态，但并不假设存在平衡状态。 我们向几何布朗运动（GBM）添加了再分配：所有个体按其财富比例进行贡献，并获得所收集金额的相等份额。 我们拟合了使模型能够重现1917年至2012年美国观察到的财富不平等所需的再分配率参数。 我们发现，直到20世纪80年代，该比率都是正的，此后变为负值且绝对值不断增加。 在负的再分配下，系统无法达到平衡。 即使在观察到的正再分配率下，平衡过程也过于缓慢，因此在实践中无关紧要。 因此，那些假设平衡的研究必须持怀疑态度。 由于设计原因，它们无法检测到在此处发现的剧烈条件，当数据在没有此约束的情况下进行分析时。 显示英文摘要

摘要： Studies of wealth inequality often assume that an observed wealth distribution reflects a system in equilibrium. This constraint is rarely tested empirically. We introduce a simple model that allows equilibrium but does not assume it. To geometric Brownian motion (GBM) we add reallocation: all individuals contribute in proportion to their wealth and receive equal shares of the amount collected. We fit the reallocation rate parameter required for the model to reproduce observed wealth inequality in the United States from 1917 to 2012. We find that this rate was positive until the 1980s, after which it became negative and of increasing magnitude. With negative reallocation, the system cannot equilibrate. Even with the positive reallocation rates observed, equilibration is too slow to be practically relevant. Therefore, studies which assume equilibrium must be treated skeptically. By design they are unable to detect the dramatic conditions found here when data are analysed without this constraint.