Unequal Gains is a game-changing work, inviting or perhaps impelling economic historians to revise a core narrative of their field, in which the fledgling U.S. economy gradually overtook the United Kingdom across the nineteenth century, attaining world leadership only after 1900. To the contrary, argue Peter Lindert and Jeffrey Williamson, the thirteen colonies were already world real-income leaders in 1774, and for some time before that, regaining that status prior to the Civil War only to lose it a second time in the wake of destructive wars and postwar dislocations.

Venturing back into a statistical dark age, Lindert and Williamson adapt the venerable methodology of “social tables” to the new purpose of generating gross domestic product (GDP) estimates for benchmark years: 1774, 1800, 1850, 1860, and 1870. They make a plausible case that wage and property data for such categories as officials, merchants, artisans, farm operators, and laborers are more abundant and reliable than production-side extrapolations from exports or guesses on household production. An attractive feature of the method is that it simultaneously generates estimates of inequality—albeit neglecting variation within categories—and the authors find that mainland colonial British America was not only the world's richest economy, but one in which “incomes were more equally distributed . . . than in any other places that can be measured” (p. 37). Acknowledging that they cannot do full justice to the status of slaves within this framework, the authors do not shrink from reporting that “even American slaves were above the bottom of the Anglo-American income ladder” (p. 38). Although wealthy Londoners may have enjoyed cheaper “free domestic servants, fashion wear, carriages, fine wines, and tickets to Handel concerts,” the figures provide quantitative support for the saying that colonial North America was the “best poor man's country” for the vast majority (p. 73).

One concern is that the new income-based GDP estimates are systematically higher than alternatives from the supply side, by roughly 20 percent for 1774 and 26 percent for 1860 (pp. 28, 97). Conceptually, of course, the two methods should be equivalent, and the authors speculate that the difference may arise from “flawed price deflators” or from underreporting of the service sector in production-side studies (pp. 97, 144). In the absence of full reconciliation, however, the claims regarding international comparisons deserve some skepticism, since the British GDP estimates by Stephen Broadberry and colleagues (British Economic Growth, 1270–1870 [2015]) were not generated by similar methods. Estimates of levels and growth over time within the United States are more clearly comparable.

To this reviewer, the most interesting new finding is that “the southern reversal of fortune started early”: the southern colonies (Chesapeake and Lower South) were by far the most affluent in the eighteenth century, even when slaves are included in the regional population. Although all parts of the country suffered setbacks between 1775 and 1800 (perhaps mainly between 1775 and 1790, though Lindert and Williamson use 1800 as their benchmark in order to use the records from the short-lived federal tax of 1798), but the absolute decline was most severe in the South. Presumably the southern economy was more affected by the loss of long-distance markets during this period, as well as by disruptions to slavery. It is nonetheless striking that these post-Revolutionary regional losses were never recovered, and that even with the rise of the cotton economy from the 1790s, the southern per capita growth rate between 1800 and 1860 (0.9 percent per year) was well below that of New England (1.94 percent) or the Mid-Atlantic (1.66 percent) (p. 102). These longer-term growth estimates will provide a useful addition to recently revived debates on the economics of slavery.

It is possible, however, that the 1774 southern estimates are too high. They derive primarily from returns on the capitalized value of slave labor, which may have been volatile, but also on a new research finding, based on tax lists for three rural North Carolina counties, that there were virtually no propertyless white southern households in that year (pp. 34–35). Since the new states of Virginia, North Carolina, and South Carolina passed at least fifty-two measures dealing with paupers and vagrants between 1776 and 1800 (James W. Ely, “Poor Laws of the Post-Revolutionary South, 1776–1800,” Tulsa Law Journal [1985]), it may be that the authors missed some poor white colonial southerners. Although they argue that even a 10 percent undercount would not alter their main findings, the regional comparison of class structures invites more detailed scrutiny by specialists (p. 36).

The same is true for the broader account of regional “reversal of fortune.” The South experienced only relative decline to 1860, but the Civil War chapter reports that absolute losses for white southerners between 1860 and 1870 were as great as those of the period from 1774 to 1800 (nearly 30 percent). The authors state candidly that they are not sure of the reasons for this pattern. They mention the possibility of “some fundamental institutional weakness associated with slavery,” but they express skepticism about this view because of the South's rapid growth between 1840 and 1860, “which wasn't driven by a boom in the price of the region's new export staple, cotton” (p. 110). This remark overlooks the fact that the price of cotton was endogenous to American supply; if we look more appropriately at cotton demand during these years, we find that the late antebellum cotton boom was indeed driven by extraordinary, though unsustainable, growth in demand for the South's export staple. A straightforward explanation for enduring regional losses during the wartime decade is that the antebellum South was the wealthiest region in the nation when slave values are included, but the poorest when they are not (Wright, Slavery and American Economic Development [2006], p. 60).

The later chapters bring the story of U.S. growth and inequality to the present, with fewer new results and hence fewer surprises, but nonetheless are a useful survey for general readers. For the book as a whole, the authors deserve high praise not only for the originality of their research but for the transparency of their project, reflected in detailed appendices and Internet files (http://gpih.ucdavis.edu). Their open invitation and encouragement to skeptics to retrace their steps and revise the results sets a new standard for research in the digital era.