Patents, News, and Business Cycles
利用专利申请数据构建工具变量，识别技术新闻冲击，发现其短期内不影响全要素生产率但驱动长期趋势，引发经济扩张，但对经济周期波动的解释力有限。
Abstract We exploit information in patent applications to construct an instrumental variable for the identification of technology news shocks that relaxes all the identifying assumptions traditionally used in the literature. The instrument recovers news shocks that have no effect on aggregate productivity in the short-run, but are a significant driver of its trend component. The shock prompts a broad-based expansion in anticipation of the future increase in total factor productivity (TFP), with output, consumption, and investment all rising well before any material increase in TFP is recorded. Despite the positive conditional comovements, the shock only accounts for a modest share of fluctuations of macroeconomic aggregates at business cycle frequencies. Financial markets price-in news shocks on impact, while most of the macro aggregates respond with some delay.