Increase in frequency of citation by SCIE journals of non-Medline journals after listing in an open access full-text database

We hypothesized that it is not open access status but rather exposure in the PubMed platform that affects citation frequency in medical journals. In November 2008, medical journals from Korea began to be added to PubMed Central (PMC). Therefore, it would be interesting to know whether or not their impact factor based on Web of Science has increased since the journals were listed in PMC/PubMed. To answer this question, a citation analysis of seven journals that have been indexed in PMC since 2008 or 2009 was done. Only non-Medline journals were selected and the impact factors of five Medline journals were compared. The impact factor was calculated via Web of Science. Journal Citation Reports (JCR) data were used if the data of the target journals were provided in JCR. Trends for the impact factors of different years were analyzed using dBSTAT ver. 5.0. There has been an increasing rates of the impact factor for the seven non-Medline journals, 1.92 in 2011 over 2010 ; 3.27 in 2010 over 2009 ; 1.12 in 2012 over 2011. As for the five Medline journals, the increasing rate in 2010 over 2009 was 1.18 ; however, those of 2011 over 2010 and 2012 over 2011 were 1.01 and 1.04 respectively. The Science Citation Index Expanded impact factor of medical journals published in Korea can be increased if those journals are published in English and listed in PMC. This is an effect of the platform in which the journals are listed and not just an effect of free access