Book Reviews

30 junho, 2006

68) Democratização do sistema de patentes nos EUA

------------ EH.NET BOOK REVIEW -------------- Published by EH.NET (June 2006)

B. Zorina Khan
The Democratization of Invention: Patents and Copyrights in American Economic Development, 1790-1920
New York: Cambridge University Press, 2005. ix + 322 pp. $60 (cloth), ISBN: 0-521-81135-X.

Reviewed for EH.NET by Robert A. Margo, Department of Economics, Boston University.

If one had to list the top five issues in economic history, technical change would surely be among them. Institutions and institutional change, of course, would also be on the list. But the connection between the two -- institutions and technical change -- is certainly understudied by cliometricians. Zorina Khan's new book is meant to help remedy this situation by focusing on the role of intellectual property institutions -- patents and copyrights -- in technical progress in nineteenth-century America. (Khan is an associate professor of economics at Bowdoin College, and a Research Associate of the National Bureau of Economic Research.)

_Democratization_ is divided into ten chapters and an index (there is no separate bibliography). After an introduction that sets the stage and makes a case for the use of patent statistics and related data, chapter two surveys the legal history of patent systems in France, England, and the United States. In comparison with France, the American system was less arbitrary; in comparison with England, it was far less costly, opening up the possibility of ordinary Americans obtaining a patent.

Chapter three examines outcomes in the universe of reported cases of patent litigation before the Civil War. Khan's analysis reveals, among other results, that the shift in 1836 to patent examinations (in the application/granting process) was associated with an increase in favorable outcomes for plaintiffs, which Khan (p. 99) attributes to the greater likelihood that the "Patent Office would ... filter out those claims that failed to meet the standards for novelty" thereby altering the set of cases that went to trial. Chapter four studies another novel data set on antebellum patentees. Over time, patenting per capita increased, not because of a greater likelihood of invention among a small, core elite, but rather an increase in the proportion of individuals who patented. Patenting was also correlated
with various features of local economies that suggest a role for market expansion, such as urbanization or access to transportation networks.

Chapters five and six switch gears, focusing on female patentees. Khan argues that women's role in technical change has been slighted in favor of other topics (such as labor force participation). Although women were far less likely to be patentees than men, there was growth over time -- indeed more rapid growth among women later in
the century -- and certain patterns suggest responsiveness to market signals. In Chapter six, Khan uses a data set on married women's property laws to test whether the passage of such laws -- a form of economic emancipation -- raised the probability that women would engage in patenting. Chapter seven returns to the basic theme, showing that "great inventors" of the nineteenth century were also, in many ways, not very distinguishable from ordinary Americans.

To this reviewer, Chapters eight and nine are perhaps the most interesting in the book. Chapter eight, sort of a reprise of chapter two, elucidates the history of copyright in the United States against a European background. By comparison, American copyright emphasized widespread access to intellectual output whereas the European model (that is, the French) imagined that authors had natural rights to
their work. Chapter nine is an entertaining analysis of the American refusal, until late in the nineteenth century, to extend copyright protection to "foreign" authors. Using a variety of data including a sample of book prices, Khan investigates various assertions in the literature -- for example, that the policy permitted book publishers to charge lower prices for foreign authors (apparently not). Chapter
ten summarizes the central findings and also further explores variations in patent systems across countries and economic outcomes.

_Democratization_ has many virtues. The general topic is, without question, of first-order importance. Above all, the book is very well-written. It is obvious from the beginning that Khan has an erudite command of the relevant literature and historical sources, both American and European, a command that is especially evident in the copious and detailed footnotes. She has a flair for telling anecdotes, written and visual, that personalize the hard numbers. The quantitative data examined in the book are fresh and quite varied. By and large, cliometricians have paid relatively little attention to historical data on legal outcomes. In this regard, the analysis of patent litigation in Chapter three may prove useful as a blueprint in other contexts.

Virtues aside, however, I found myself flagging about halfway through largely because the book's mantra -- that America possessed a patent system that was, by world standards, egalitarian -- does not seem particularly surprising and, at the very least, is of debatable economic significance. The two chapters on women, frankly, could easily have fit into one, much briefer chapter that would have better
kept this reader's attention.

For a book that is quite self-consciously "cliometric" -- there are 37 tables and 20 figures -- the cliometrics on display do not go far enough, at least for my tastes. Hypotheses to be tested are not derived from formal models but rather from the prior literature and, consequently, the connection to the empirical work can seem vague
(as, for example, in the claim mentioned at various points that the preponderance of ordinary Americans among patentees sheds useful light on Joel Mokyr's well-known distinction between macro- and micro-inventions). The many regressions are descriptive exercises -- multivariate versions of (the many) two-way tables, if you will. As such, the coefficients are subject to multiple interpretations that
are not always considered in sufficient detail to convince a skeptical reader of Khan's preferred spin. For example, in her econometric analysis of patent specialization (Table 4.3), Khan draws on previous work by Kenneth Sokoloff (_Journal of Economic History_ 1988) to give a plausible explanation of the negative coefficient of the presence of a navigable waterway. The "average patentee," we are
told (p. 121), "became less specialized when water transportation became available, but ... this change was reversed over time as urbanization ... progressed." This may be true, but it imposes a dynamic interpretation on an econometric specification that is not designed for this purpose. In another example, Table 6.4 reports
regressions that claim to show that states that passed married women's property laws experienced increases in female patenting that were statistically and economically (given the low base) significant. This, too, may be true but, as best as I can tell, the econometric analysis is not true difference-in-difference, and potential
endogeneity issues regarding the laws do not seem to be fully explored.

Criticisms aside, _Democratization_ is an important book on a subject -- the economic history of intellectual property -- that heretofore has received insufficient attention from economic historians. The book's style of argument emphasizing a wide array of sources will appeal to a much broader audience than is usually the case with monographs in economic history. And it will be a very good thing if Khan's quantitative work with historical legal documents stimulates
others to follow suit.

Robert A. Margo is Professor of Economics and African-American Studies, Boston University; and Research Associate, National Bureau of Economic Research. He is the editor of _Explorations in Economic History_.

Copyright (c) 2006 by EH.Net. All rights reserved. This work may be copied for non-profit educational uses if proper credit is given to the author and the list. For other permission, please contact the EH.Net Administrator (; Telephone: 513-529-2229). Published by EH.Net (June 2006). All EH.Net reviews are archived at

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