Carrie links to a Wall Street Journal article about scientific journals that encourage authors to refer to other articles from the same journal:
John B. West has had his share of requests, suggestions and demands from the scientific journals where he submits his research papers, but this one stopped him cold. . . After he submitted a paper on the design of the human lung to the American Journal of Respiratory and Critical Care Medicine, an editor emailed him that the paper was basically fine. There was just one thing: Dr. West should cite more studies that had appeared in the respiratory journal. . . . “I was appalled,” says Dr. West of the request. “This was a clear abuse of the system because they were trying to rig their impact factor.” . . .
The result, says Martin Frank, executive director of the American Physiological Society, which publishes 14 journals, is that “we have become whores to the impact factor.” He adds that his society doesn’t engage in these practices. . . .
From my discussions with Aleks and others, I have the impression that impact factors are taken more seriously in Europe than in the U.S. They also depend on the field. The Wall Street Journal article says that impact factors “less than 2 are considered low.” In statistics, though, an impact factor of 2 would be great (JASA and JRSS are between 1 and 2, Biometrics and Biometrika are around 1). Among the top stat journals are Statistics in Medicine (1.4) and Statistical Methods in Medical Research (1.9), which are considered OK but not top stat journals. You gotta reach those doctors (or the computer scientists and physicists; they cite each other a lot).