Technological Diversification
提出一个技术多样化模型，解释为何早期经济体增长波动大而发达经济体增长稳定。模型表明企业采用投入品种能提高平均生产率并分散风险，导致波动随发展下降。
Economies at early stages of development are frequently shaken by large changes in growth rates, whereas advanced economies tend to experience relatively stable growth rates. To explain this pattern, we propose a model of technological diversification. Production makes use of input-varieties that are subject to imperfectly correlated shocks. Endogenous variety adoption by firms raises average productivity and provides diversification benefits against variety-specific shocks. Firm-level and aggregate volatility thus decline as a by-product of the development process. We quantitatively assess the model's predictions and find that it can generate patterns of volatility and development consistent with the data.