hile Canada’s output of scientific papers has been relatively flat in recent years, and the nation’s share of the world scientific literature has actually dipped, the overall citation impact of Canadian research appears to be in solid health, according to a new Science Watch survey.

Science Watch turned to National Science Indicators, a Thomson/ISI evaluation tool, to examine Canadian research over the last 21 years. The graph to the left tracks the percentage share of ISI-indexed scientific literature since 1981 (that is, each nation’s percentage of papers indexed by ISI from all fields of science and social sciences during each of the last 21 years) for Canada and eight other nations of roughly comparable scientific output. As the graph shows, some of the nations—Japan, Italy, and especially China—are clearly on an upward trend in their overall share of the literature. Others, like France, Australia, and Germany, appear to be leveling off after periods of slow but steady growth. Canada, however, shows an unmistakable slide in percent, or world, share. From an initial score of 4.51% of papers in 1981, and after a zenith of 5.19% achieved in 1993, Canadian papers accounted for 4.38% of the database in 2001.

Canada, of course, is not alone in seeing its share of the literature shrink in recent years. Indeed, the percentage of U.S. papers indexed by ISI has also declined steadily during the last two decades—from 40% in 1981 to just over 34% in 2001. As was noted in these pages five years ago, the nations of the European Union, the Asia Pacific region, and Latin America have seen their collective shares of world science rise in recent decades, as the United States has found itself losing ground in what is a zero-sum game (see Science Watch, 8[3]:1-2, May/June 1997). As other nations, particularly those in Asia, have increased their output rapidly and chosen more and more to publish in the internationally influential journal literature that ISI indexes, it is only natural that U.S. and other nations’ world share would decline. Canada, it would seem, is also being affected by this inexorable shift to greater globalization in the scientific landscape.

At the same time, however, Canada’s overall output in science (that is, its absolute number of papers indexed by ISI each year), after a rise through the 1980s, has maintained a discernible plateau for the last decade or so. In fact, as can be seen from the table on the right, after producing more than 33,000 ISI-indexed papers in 1995 and 1996, Canada slipped back towards 31,000 for the next few years and has, for the last three years, hovered in the region of 32,000 papers. (Then again, this plateau would seem to be another trend that Canada shares with its North American neighbor: after a high of some 249,000 ISI-indexed papers in 1995, the United States exceeded 245,000 papers in only two of the five subsequent years, and did not rise to surpass 250,000 papers until 2001.)

Even if Canada has leveled off in its production of scientific papers in recent years, the influence of those papers appears to be increasing. The graphs at right track the relative impact of Canadian research in overlapping five-year periods from 1981 on, in 18 fields grouped into three main subject areas. For each field, Canada’s impact, or cites per paper, is compared against the field’s baseline, or world, impact figure (n = 1.00). In the physical sciences, space science (including astronomy and astrophysics) registered particularly strongly. For the period 1997-2001, in fact, the impact of Canadian papers in space science was 33% above the world mark. Canadian chemistry, too, has performed steadily above the world baseline, with a 1997-2001 impact score that exceeded the world average by 28%. Even in physical-sciences fields in which Canadian impact registered below the world average in the early 1980s—including engineering, materials science, and geosciences—impact figures rose steadily and scored above the world mark in the latest five-year period.

Similar trends are evident in the biological and medical sciences. Clinical medicine, in fact, represents Canada’s strongest relative-impact performance, with an average citation rate 34% above the world mark over the last five years. Pharmacology has also been trending upward in recent years, with a 1997-2001 average that exceeded the world figure by 20%. Canadian impact in all the other biomedical fields shown, although starting the two-decade period below the world average, now surpasses the world figure—if only modestly in some fields. In molecular biology & genetics, for example, Canada’s relative-impact score was just +1% for the last five years. Even in agricultural sciences, the one field in which Canadian impact has primarily trended downward over the two decades, impact is still above the world average, and even shows signs of an upswing in recent years.