This paper explores the patterns of citations among patents taken out by inventors in the U.S., the U.K., France, Germany and Japan. We find (1) patents assigned to the same firm are more likely to cite each other, and come sooner than other citations; (2) patents in the same patent class are...

This paper explores the patterns of citations among patents taken out by inventors in the U.S., the U.K., France, Germany and Japan. We find (1) patents assigned to the same firm are more likely to cite each other, and come sooner than other citations; (2) patents in the same patent class are...

Studies of firm-level data have shown that a firm's R&D and the R&D of other firms increase conventional factor productivity. We investigate these phenomena further by examining the relationship between plant-level productivity and firm-level R&D. We find that (1) the productivity-enhancing...

This paper presents estimates of the depreciation rate of innovations using survey data on revenues associated with Australian patents. Its novelty is twofold. First, it relies on direct observation of the revenue streams of inventions. This is in sharp contrast with previous studies, which all...