COSTLY INTERMEDIATION AND THE POVERTY OF NATIONS*
通过引入公共资本的中介成本和私人投资的信贷摩擦，将解释全球最富与最穷国家33倍收入差距所需的生产率差异从7倍降至3倍，引入家庭生产部门后进一步降至2.1倍。
This article has two goals: (i) to reduce the 7‐fold productivity differential required to explain the observed 33‐fold income difference between the richest and poorest countries of the world; and (ii) to explain cross‐country differences in the capital‐output ratio. To achieve the first goal we modify the production function of the standard neoclassical growth model to include public capital whose provision is subject to intermediation costs. For the second goal we distort private investment by introducing credit frictions. The model, quantified using cross‐country data, generates an income gap of 33 with productivity differences of only 3 under the measured variations in public and private capital. The required productivity gap declines even further, to 2.1, when we introduce a home‐production sector. On the second goal, however, credit frictions do a poor job of explaining cross‐country variations in the capital‐output ratio.