U.S. legal changes have made it easier to obtain patents on inventions that use software. Software patents have grown rapidly and now comprise 15 percent of all patents. They are acquired primarily by large manufacturing firms in industries known for strategic patenting; only 5 percent belong to...

Do patents provide critical incentives to encourage investment in innovation? Or, instead, do patents impose legal risks and burdens on innovators that discourage innovation, as some critics now claim? This paper reviews empirical economic evidence on how well patents perform as a property system.

A simple formal model shows that estimates of an upper bound on the value of firms' patent rents can be obtained from regressions on Tobin's Q. I test this model on a sample of US firms and find it is robust to a variety of considerations. The estimates correspond well with implied estimates...

Solow (1957) decomposed labor productivity growth into two components that are independent under Hicks neutrality: input growth and the residual, representing technical change. However, when technical change is Hicks biased, input growth is no longer independent of technical change, leading to...

This paper uses renewal data to estimate the value of U.S. patents, controlling for patent and owner characteristics. Estimates of U.S. patent value are substantially larger than estimates for European patents, however, the ratio of U.S. patent value to R&D for firms is only about 3%. Patents...

This paper estimates the total cost of patent litigation to alleged infringers. We use a large sample of stock market event studies around the date of lawsuit filings for US public firms from 1984-99. We find that the total costs of litigation are much greater than legal fees and costs are large...

This paper uses renewal data to estimate the value of U.S. patents, controlling for patent and owner characteristics. Estimates of U.S. patent value are substantially larger than estimates for European patents, however, the ratio of U.S. patent value to R&D for firms is only about 3%. Contrary...