preparing and printing papers, by journal 

 refereeing and publishing policies, etc. These 

 factors provide good reason for caution in 

 interpreting such indicators. 



The data presented here are the results of an 

 initial attempt to: 



(1) Estimate the proportion of the world's 

 significant research and technical 

 literature (in selected scientific areas) 

 which is produced by the United States 

 and other major countries, and 



(2) Assign a figure of merit representing 

 the quality or significance of the litera- 

 ture produced in each area by each 

 country. 



The scientific areas and countries encom- 

 passed are shown below: 



Sciet^lific Areas 



Physics and Geophysics 

 Chemistry and Metallurgy 

 Molecular Biology 

 Systematic Biology 

 Psychology 

 Economics 

 Mathematics 

 Engineering 



Countries 



France 



Japan 



United Kingdom 



United States 



U.S.S.R. 



West Germany 



National Origins of Literature. Estimates of the 

 distribution of literature among fields and coun- 

 tries were based upon counts of articles, letters, 

 and notes published in some 500 journals 

 covered by the Science Citation }ndei (published by 

 the Institute for Scientific Information, 

 Philadelphia, Pa.), supplemented by data from 

 various abstracting services.-' The results are 

 presented in figure 4. 



-' For details of the methodology employed, including 

 validation checks, see DevelopmenI of U.S. and Intenmtional 

 liut)calori of the Quantity and Quality of Siienlific Literature. 

 Computer Horizons, Inc., September 1972. 



The United States has a larger share of the 

 literature in each of the areas (except for chemis- 

 try and metallurgy) than any othercountry. The 

 U.S. share, as well as those of other countries, 

 shows little change over the short period (1965- 

 71) covered by the data. 



In the area of physics and geophysics, the 

 United States produces some 40 percent of the 

 literature, as compared with about 15 percent 

 from the U.S.S.R., and between 5 to 8 percent 

 from each of the other four countries. How- 

 ever, in the other physical science 

 area — chemistry and metallurgy — the U.S.S.R. 

 has the largest share with some 29 percent, 

 versus the 24-percent share of the United States, 

 and the 5- to 9-percent share of each of the other 

 four countries. 



In molecular biology the United States 

 produces almost one-half the world's literature, 

 with each of the two next largest producers 

 (United Kingdom and France) having shares of 

 only 9 percent. The U.S. share of the systematic 

 biology literature is considerably less, at some 30 

 percent, than molecular biology, but still ex- 

 ceeds that of any other individual country by a 

 wide margin. 



In psychology and economics, literature of 

 U.S. origin represents the largest share. The 

 available data for both areas, however, were 

 more limited and less reliable than data for other 

 areas. In spite of these limitations, the relative 

 position of the United States in each area is 

 believed to be accurately reflected by the data. 



In mathematics the United States and U.S.S.R. 

 share the lead as the major literature producers, 

 with the United States having a slightly larger 

 share. The shares of the other four countries 

 range from 4 to 7 percent. 



In engineering the United States produces 

 about 50 percent of the world's literature. The 

 next largest producers are the U.S.S.R. with 12 

 percent, and the United Kingdom with about 10 

 percent. 



Literature Citations. In addition to the purely 

 quantitative aspects, an effort was made to esti- 

 mate the relative "quality" or "significance" of 

 the literature. The basis for this indicator was 

 the number of citations to the literature 



