Scholars are gradually piecing together the puzzle of the economic development of the American colonies through quantitative studies designed to clarify and measure economic variables having theoretical relevance for the wider process of economic growth and development. Recently, researchers such as Jones, Land, Shepherd, Walton, and Thomas have been helping others to build a base that one day may permit the writing of a comprehensive study of the process of early American economic development which may even include reliable estimates of economic growth and living standards. The data problems for the colonial period of American economic history are severe, and much of the research has tended to concentrate on the important role of international trade, where the extant data sources are capable of yielding rich lodes of quantitative information. Customs 16/1, entitled the Ledger of Imports and Exports for America, 1768–1772, has been the most valuable source of trade data, since it is the only comprehensive document which shows the trade of the American colonies with all parts of the world and not just with the British Isles. Still yet to be mined are the rich sources of data buried in the naval office lists for the various colonies. These sources also give the trade of each colony with all parts of the world although they are more tedious to work with than the better collated Customs 16/1.

Systematic demographic analysis of early America has been neglected until quite recently. As the interest in and need for demographic data on pre-1800 America have increased during the last five years, efforts have been made to remedy this situation.The most recent studies are utilizing such new techniques as family reconstitution to avoid the problems created by the lack of reliable census data and vital statistics. But these techniques yield results very slowly, and in any case their results are subject to methodological limitations that make it necessary to check them against larger aggregates. For these reasons we need to reexamine the usefulness and accuracy of earlier studies on colonial population that were based on aggregate data. Unfortunately, this latter task has not been adequately carried out during the recent burst of activity among demographers of early America.

In the past decade the question of the degree of mutual economic dependence among the three major regions of the antebellum United States—Northeast, South, and West—has received considerable discussion. Good indicators of the degree of dependence would be ratios of the interregional trade flows of particular commodities to the amounts of those commodities produced locally in each region. Trade data are available, however, only in limited series for major cities or commercial areas. Since comprehensive trade flows cannot be measured directly, various indirect approaches to the question have been employed.

Alone woodsman erecting a log cabin, wagon trains curling across the prairies, fur trappers high in the mountains, Indian war parties, gold strikes, frontier marshalls and gunmen—of such stuff the legends of the American West have been formed and in the popular imagination they are the Westward Movement. Of course, serious historians have long recognized that this is merely a fascinating but veneer-like overlay which disguises a massive movement of people from East to West.

British investment in Argentina in the period 1880–1914 amounted to some 8 percent of total British overseas investment; it exhibited long swings which were roughly similar to long swings in total British overseas investment but opposite to British domestic investment, although the bursts of lending to Argentina were particularly concentrated. These swings have attracted the attention of economists and some (notably Brinley Thomas) have pointed out that emigration from Europe to North America and American investment in construction and transportation and other series in the American economy exhibited 18–20 year swings similar to those in British overseas investment, and that these were all in opposite phase to swings in British home investment and the building cycle in Britain. They have then gone on to explain these inverse British patterns in terms of emigration and the growth rhythm of the Atlantic economy, with heavy stress being laid on North American effects. The analysis of movements of both labor and capital can then be conducted in terms of the varying intensities of the pull of opportunities at home and abroad, and the push of home conditions and prospects, and how these interacted with each other to produce these inverse patterns.

Recently an article by Samuel Pao-San Ho appeared in this Journal, which, while using some of the data from my previous study of Taiwan's agriculture, criticizes the input series I compiled. Samuel Ho offers competing estimates of productivity change and its sources, and provides estimates of the transferred agricultural surplus and an interpretation of the transfer process. His estimates of the productivity change in Taiwan's agriculture during the colonial period are considerably lower than my own.

In his comment on my 1968 article, Professor Y. M. Ho questions: (1) my selection of input measurements, (2) my explanation of the residual, and (3) my discussion of the agricultural surplus. I shall comment on each of these issues in turn.