Scale versus scope in the diffusion of new technology: evidence from the farm tractor
研究了拖拉机从有限用途到通用化的扩散过程，发现早期扩散在特定用途上迅速，但用途范围扩展缓慢，这对理解技术扩散的广度与深度有启示。
Abstract Although tractors are now used in nearly every agricultural field operation and in the production of nearly all crops, they first developed with much more limited application. Early diffusion was accordingly rapid in these narrower applications but limited in scope until tractor technology generalized. The sequence of diffusion is consistent with a model of Research and Development (R&D) in specific‐ versus general‐purpose attributes and with other historical examples, suggesting that the key to understanding technology diffusion lies not only in explaining the number of different users, but also in explaining the number of different uses .