PEARSON'S RXY vs COSINE SIMILARITY FOR CO-AUTHOR COCITATION

This page shows crossplots of Pearson rxy against cosine formula similarities from 27 collections of papers covering various subjects. For each collection of papers the 200 most cited reference authors were used. A paper to reference author matrix, O(p,ra) was constructed. The (i,j)th element of O(p,ra) is unity if paper i cites reference author j one or more times, zero otherwise. Author co-citation counts were obtained by pre-multiplying O(p,ra) by its transpose. N is the number of papers in the collection, n(i) is the number of citations received by ref author i, n(i,j) is the number of papers citing both ref author i and ref author j. The correlation coefficient is calculated from rxy=[N*n(i,j)-n(i)*n(j)]/sqrt[(N*n(i)-n(i)^2)*(N*n(j)-n(j)^2)] while the cosine similarity was calulated using s=n(i,j)/sqrt[n(i)*n(j)] . The rxy and cosine s values are crossplotted below. Rxy is on the x axis and cosine s is on the y axis. These papers were collected from ISI's Web of Science product in the period from January 2002 to December 2003 by using queries and seed references.