This paper studies aggregate equilibrium models where firms cannot compute future prices with perfect accuracy. Instead, firms use approximations to infer prices. In equilibrium, we find that the precision with which firms can compute prices is endogenous and depends on the level of aggregate supply. At the same time, firms’ individual supplies, and thus aggregate supply, depend on the precision with which future prices are computed. This interplay between supply and firms’ individual ability to infer prices induces multiple equilibria, with inefficiently low output, in economies that otherwise have a unique, efficient, rational expectations equilibrium. Moreover, exogenous parameter changes, which would increase output were there no computational frictions, can diminish the precision of agents’ price forecasts, and reduce output. Our model also accommodates the intuition that large interventions, such as unprecedented quantitative easing, can put agents into “uncharted territory.”

本文研究了总均衡模型，在这些模型中，企业无法准确地计算未来价格。相反，企业使用近似值来推断价格。在均衡状态下，我们发现企业计算价格的精度是内生的，并且取决于总供给水平。同时，企业的个体供给，进而总供给，取决于计算未来价格的精度。在本来具有独特，有效，理性预期均衡的经济体中，供应与企业个人推论价格能力之间的这种相互作用会导致多重均衡，而低效率的低产出。而且，如果没有计算上的摩擦，外来的参数变化会增加产量，从而降低代理商价格预测的准确性并降低产量。