This paper uses wavelets to decompose each stock's trading-volume variance into frequency-specific components. We find that stocks dominated by short-run fluctuations in trading volume have abnormal returns that are 1% per month higher than otherwise similar stocks where short-run fluctuations...

This paper uses a large language model to develop an ex-ante measure of the commercial potential of scientific findings. In addition to validating the measure against the typical holdout sample, we validate it externally against 1.) the progression of scientific findings through a major...

Local opinion leaders may play a key role in easing information frictions associated with technology adoption. This paper analyzes the influence of physician investigators who lead clinical trials for new cancer drugs. By comparing diffusion patterns across 21 new cancer drugs, we separate...

Investment in research and development (R&D) affects a country's total factor productivity. Recently new theories of economic growth have emphasized this link and have also identified a number of channels through which a country's R&D affects total factor productivity of its trade partners....

In this paper we analyze the evidence from a large number of studies on three specific questions pertaining to R&D investment: (1) Are there diminishing returns to inventive activities? (2) What is the relationship between R&D and productivity and what are the magnitudes of the returns to a...

Are scientific knowledge flows embodied in individuals, or "in the air"? To answer this question, we measure the effect of labor mobility in a sample of 9,483 elite academic life scientists on the citation trajectories associated with individual articles (resp. patents) published (resp. granted)...

The importance of new technologies derives from the fact that they spread across many different users and uses, as well as different geographic regions. The diffusion of technological improvements, across producers within a country and across international borders, is critical for long run...

Estimation of our model for a sample of 19 technologies, 21 countries, and the period 1870-1998 reveals that embodied productivity growth is large for many of the technologies in our sample. On average, increases in the variety of vintages available is a more important source of growth than the...

This paper presents a new data set on the diffusion of about 115 technologies in over 150 countries over the last 200 years. We use this comprehensive data set to uncover general patterns of technology diffusion. Our main 5 findings are as follows: (i) Once the intensive margin is measured,...

I discuss the concept and empirical importance of international technology diffusion from the point of view of recent work on endogenous technological change. In this literature, technology is viewed as technological knowledge. I first review the major concepts, and how international technology...