The least productive agents in an economy can be vital in generating growth by spurring technology diffusion. We develop an analytically tractable model in which growth is created as a positive externality from risk taking by firms at the bottom of the productivity distribution imitating more productive firms. Heterogeneous firms choose to produce or pay a cost and search within the economy to upgrade their technology. Sustained growth comes from the feedback between the endogenously determined distribution of productivity, as evolved from past search decisions, and an optimal, forward-looking search policy. The growth rate depends on characteristics of the productivity distribution, with a thicker-tailed distribution leading to more growth.

and various seminar participants for useful comments and suggestions. Aref Bolandnazar and Brad Hackinen provided excellent research assistance. Jesse Perla gratefully acknowledges support from the University of British Columbia Hampton Grant. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

We study how opening to trade affects economic growth in a model where heterogeneous firms can choose to adopt a new technology already in use by other firms. We characterize the growth rate using summary statistics of the profit distribution-the ratio of profits between the average and marginal adopting firm. Opening to trade increases the spread in profits through increased export opportunities and foreign competition, induces more rapid technology adoption, and generates faster growth. Quantitatively, opening to trade yields large increases in growth, but welfare effects are muted due to loss of variety and reallocation of labor away from production.

We would like to thank Boyan Jovanovic and Tom Sargent for useful feedback. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. NBER working papers are circulated for discussion and comment purposes. They have not been peerreviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

We study how opening to trade affects economic growth in a model where heterogeneous firms can adopt new technologies already in use by other firms in their home country. We characterize the growth rate using a summary statistic of the profit distribution: the mean-min ratio. Opening to trade increases the profit spread through increased export opportunities and foreign competition, induces more rapid technology adoption, and generates faster growth. Quantitatively, these forces produce large welfare gains from trade by increasing an inefficiently low rate of technology adoption and economic growth. (JEL D21, D24, F14, F43, O33)