The Demography of Corporations and Industries (2000) by Glenn R. Carroll and T. Michael Hannan is a welcome addition to a body of empirical analysis of firms and industries that studies the effects of technological change and other changes that occur over time. The book contains a wealth of facts, and some new insights too. It will make useful secondary reading in some graduate courses in economics, and I would recommend it to anyone whose research relates to the concept of creative destruction.

Why did the stock market decline so much in the early 1970's and remain low until the early 1980's? We argue that it was because information technology arrived on the scene and the stock-market incumbents of the day were not ready to implement it. Instead, new firms would bring in the new technology after the mid-1980's. Investors foresaw this in the early 1970's and stock prices fell right away. In our model, new capital destroys old capital, but with a lag. The prospect of this causes the value of the old capital to fall right away.

Firms that entered the stock market in the 1990s were younger than any earlier cohort since World War I. Surprisingly, however, firms that IPO'd at the close of the 19th century were just as young as the companies that are entering today. We argue here that the electrification-era and the IT-era firms came in young because the technologies that they brought in were too productive to be kept out very long. The model assumes that the stage before IPO is a learning period during which the firm refines the idea before committing to it at the IPO stage. The better the idea, the higher is the opportunity cost of a delay in its implementation, and the earlier the firm will have its IPO.