The routine portfolio.exe provides an overlay of journals in a document set retrieved from the Web-of-Science (WoS) onto the global journal map 2012 provided at http://www.leydesdorff.net/journals12 . The resulting figure (in VOSviewer) can be used for inspection of a portfolio; one can also make overlays for different years, and thus generate animations using PowerPoint.
1. Preparing input files
a. Generate a document set at the user interface of the Web-of-Science (WoS) on the basis of a research question; all search fields can be used;
b. Enter the document set under “Results”;
c. Click on “Analyze Results” on the top-right side of the screen;
d. At “Rank the records by this field” select “Source titles”;
e. Click on “Analyze”;
f. Select “All data rows”; “Save analysis to file”;
g. The file is saved as “analyze.txt” (or “analyze(1).txt” for next files, etc.);
h. Rename the file as convenient using only eight characters; the file extension has to remain “.txt”; choose different file names for different runs/sets;
2. Run the routine portfolio.exe
a. Preferably run from the c-prompt because of the possible error messages in this interface; however, one can also run from Windows;
b. The routine will first prompt for the file name that you provided at 1.h. above;
c. The processing may take some time depending of the number of journals involved; you can interrupt using Ctrl-Break (or Ctrl-Pause on some keyboards);
d. The routine terminates with a screen providing the values for Rao-Stirling diversity (Rao, 1982; Stirling, 2007) and diversity according to Zhang et al. (in press); the distance is measured as the Euclidean distance on the map at http://www.leydesdorff.net/journals12 (Leydesdorff et al., 2013);
e. Each run provides a file with the same name as the input file, but with the extension “.vos”. This file can be read into VOSviewer for generating a journal map; each run also provides a file “rao.txt” with the (two) values for the diversity (see 2c);
3. Output accumulated across runs of portfolio.exe
a. A file “rao.dbf” is generated at the first run that stores the values for diversity under 2d for sequential runs; the name to the input files provided under 1h are stored in the field “unit”;
b. A file “matrix.dbf” is generated which saves the distribution across journals in sequential runs; the name of the input files are used as the variable names;
c. One can begin a new sequence by deleting the existing files rao.dbf and matrix.dbf; new (empty) files with these names will be generated at the next-first run;
d. The fie matrix.dbf can be read into SPSS (etc.) for statistical analysis; note that the matrix will always contain the 10,542 journals included in the Science Citation Index 2012 and Social Science Citation Index 2012 as cases (in the rows), and the variables for the various runs as variables (in the columns);
e. The routine mtrx2cos.exe (available from here) generates additionally a file cosine.net (in the Pajek) format and coocc.dat (in UCInet format) for the network analysis and visualization of the data contained in matrix.dbf.
· Leydesdorff, L., Rafols, I., & Chen, C. (2013). Interactive Overlays of Journals and the Measurement of Interdisciplinarity on the basis of Aggregated Journal-Journal Citations. Journal of the American Society for Information Science and Technology, 64(12), 2573-2586.
· Rao, C. R. (1982). Diversity and dissimilarity coefficients: A unified approach. Theoretical Population Biology, 21(1), 24-43.
· Stirling, A. (2007). A general framework for analysing diversity in science, technology and society. Journal of the Royal Society Interface, 4(15), 707-719.
· Zhang, L., Rousseau, R., & Glänzel, W. (in press). Diversity of references as an indicator for interdisciplinarity of journals: Taking similarity between subject fields into account. Journal of the Association for Information Science and Technology.
 When one uses Scielo or Medline in WoS, the coverage will be limited to journals included in the Science Citation Index or Social Science Citation Index in 2012.