The impact factor of open access journals:data and trends

In recent years, a large debate has arisen about the citation advantage of Open Access (OA). Many studies have been conducted on different datasets and according to different perspectives, which led to different and somehow contradictory results depending on the considered disciplinary field, the researchers’ attitude and citational behaviour, and the applied methodology. One of the bibliometric indicators most used worldwide to measure citations is Impact Factor – not free from criticisms and reservations – but it has only been tested on Open Access journals once, in 2004.The aim of this preliminary work, focused on “Gold” Open Access, is to test the performance of Open Access journals with the most traditional bibliometric indicator – Impact Factor, to verify the hypothesis that unrestricted access might turn into more citations and therefore also good Impact Factor indices. Other indicators, such as Immediacy Index and 5-year Impact Factor, will be tested too. The preliminary step of the work was fixing the list of Open Access journals tracked by Thomson Reuters in «Journal Citation Reports» (JCR). JCR was compared to the Directory of Open Access Journals (DOAJ) as of 31 December of the corresponding year.As to coverage, Open Access journals in «Journal Citation Reports» are still a small percentage, even though there has been a large increase since 2003 in the Science edition (from 1.47% to 5.38%), less visible in the Social Science edition (from 1.05% to 1.52%, with a slight decrease from the 2007 1.71%).In order to obtain comparable data, absolute Impact Factor or Immediacy Index values were not considered, but rather converted into percentiles for each category. The rank of the Open Access journals was analyzed in each single category. The titles were then clustered in disciplinary macro-areas, and data were aggregated.Open Access journals in JCR 2008 Social Sciences edition rank in the top fifty percentiles (0-50) with a 54.5% share.With substantial differences between macro-areas, in JCR 2008 Science edition Open Access journals rank in the top fifty percentiles (0-50) with a 38.62% share when considering Impact Factor, and with a 37.68% share referring to Immediacy Index. When considering 5-year Impact Factor, the share is 40.45%.Open Access journals are relatively new actors in the publishing market, and gaining reputation and visibility is a complex challenge. Some of them show impressive Impact Factor trends since their first year of tracking. The collected data show that the performance of Open Access journals, also tested with the most traditional bibliometric indicator, is quite good in terms of citations