In recent years South Korea has steadily increased its share of the world's scientific literature, according to a new Science Watch^® survey. In output of published papers, South Korea now surpasses Taiwan and other neighbors in the Pacific Rim. This increase has been accompanied by a rise in the number of highly cited papers produced by South Korean institutions, as well as an upward trend in the nation's citation impact in key fields.

Science Watch last touched on South Korea seven years ago, in a study of Singapore and other "Asian Tigers"— the smaller industrialized nations of the Pacific Rim (see Science Watch 6[6]:1-2, June 1994). At that time, based on output figures through 1993, Taiwan was tops among these nations in production of scientific papers as reflected in the ISI database, besting second-place South Korea by nearly 2,000 papers. Seven years later, as the graph above shows, the situation is reversed: throughout the early 1990s South Korea and Taiwan both rose sharply in output, but in 1997 their paths intersected, and South Korea became the most scientifically prolific nation of the five shown here. In 2000, ISI^® indexed some 12,218 papers listing at least one South Korean address, compared to 9,203 papers from Taiwan. Overall, South Korea has increased its share of the ISI database from 0.05% in 1981 to 1.71% in 2000.

The table on the next page examines South Korean output more closely, breaking it down into 18 main fields, ranked according to South Korea's percentage share of each field in the ISI database for the cumulative period 1996 to 2000. By this measure, the physical sciences clearly predominate in South Korea's output. The nation's greatest share of any field is in materials science, with 4,823 South Korean papers representing nearly 4% of ISI-indexed papers in that field during the last five years. Other fields at the top of the list are engineering, computer science, physics, and chemistry. As for the life sciences: aside from two fields—microbiology and biology & biochemistry—South Korea's output in life-science specialties registered below 1% of the ISI database.

The table also shows the impact (that is, citations per paper) for South Korea in each field, along with the corresponding impact figure for the world. As it happens, the field in which South Korea was most prolific over the last five years is also the one in which it scored highest compared to the world impact baseline: with an average of 1.52 citations per paper for its material-sciences reports, South Korean research registered 21% below the world mark for the field. This matched the nation's performance in agricultural sciences (1.56 cites for South Korea versus the world average of 1.98). South Korea's performance was also comparatively strong in plant & animal sciences, space science (including astronomy and astrophysics), and mathematics.

The graph takes a more retrospective look at the relative citation impact of South Korean research, comparing it to the world average in four of the nation's most active fields, in overlapping five-year periods from 1981 to 2000. The four fields display a similar pattern—a drop in relative citation impact during the early 1980s, followed by leveling off and, during the 1990s, a steady rise. When analyzed in combination with the output figures on page one, this graph shows that during the early 1980s, as South Korea gradually increased its representation in the ISI database, relative citation impact fell. This is an expected consequence of a nation's output going from a relative handful of papers (where one or two highly cited reports might tend to artificially inflate citation impact) to a greater share of the database (in which a larger sum of papers dilutes the effect of a few citation heavyweights). In recent years, however, as South Korea has increased its share of the world literature, the nation's citation impact is unquestionably trending upward in these four key fields.

The table on the right provides another measure indicating that South Korea is increasing its presence and influence in the literature: a rise in the number of "high-impact" papers to which South Korean researchers and institutions contributed—papers that rank among the 200 most-cited papers of each year in a range of fields through 1998. In 1982, the nation managed only one such paper. From 1996 through 1998, South Korean researchers were included in at least 10 per year. Among the nation's high-impact papers published in 1998 (that is, papers chiefly from South Korean institutions, as opposed to large multinational collaborations) were reports on carbon nanotubes, gallium-nitride compounds, and other materials.

• Table:  South Korea's Research Output by Field

• Graph: South Korea's Relative Impact in Four Top Fields