Molecules 2009, 14(6), 2254-2255; doi:10.3390/molecules14062254

Editorial
Full Open Access Journals Have Increased Impact Factors
Shu-Kun Lin
Molecular Diversity Preservation International (MDPI), Matthaeusstrasse 11, CH-4057 Basel, Switzerland; Tel. +41-79 322 3379; Fax: +41-61 302 8918; E-mail: lin@mdpi.org; http://www.mdpi.org/lin
Received: 20 June 2009 / Published: 22 June 2009
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Figure 1. Impact factors of four MDPI journals (adapted from the Journal Citation Report (JCR), Edition 2008, Copyright 2009 by Thomson Reuters).

Click here to enlarge figure

Figure 1. Impact factors of four MDPI journals (adapted from the Journal Citation Report (JCR), Edition 2008, Copyright 2009 by Thomson Reuters).
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We are pleased to report the increase of the impact factors of MDPI journals during 2007 and 2008 (see Figure 1). In 2005 and part of 2006, the use of a two tier publication system, whereby we offered full Open Access publication to those authors willing to contribute financially to support this option, while providing the alternative choice of free publication withoutOpen Access for those authors who preferred not to pay [1,2], resulted in the obviously decreased impact factors seen in 2006 [3,4]. In early 2007, a full Open Access publishing policy was instituted and we can now begin to clearly see the effect of the full Open Access policy in the steady recovery of the impact factors of the affected journals.

On the other hand, the two tier publication system (Open Access and non-Open Access) was only briefly applied to the journal Sensors and we thus see a continuous increase of the impact factor in recent years. The 2008 impact factor of the journal Sensors is 1.870.

We also observed an interesting phenomenon: two Molecules papers were retracted because they had also been published elsewhere. Nevertheless, these withdrawn papers were cited elsewhere, while the non-Open Access papers were not. We have now added a watermark to the original PDF files of withdrawn papers, clearly identifying their status, in order to prevent further citation of such papers [5].

Since October 2008, all MDPI journals have been published at the new server www.mdpi.com. Just recently we published the 5000th paper in a MDPI journal and Molecules alone has published over 2000 papers. As we wrote in our editorial [6], the year 2009 will be a more successful year for the journal Molecules and for all the other MDPI journals, including several newly launched journals.

References

  1. Lin, S.-K. Open Access and Author's Open Choice. Molecules 2005, 10, 583–584, doi:10.3390/10060583.
  2. Lin, S.-K. Delayed Open Access or Permanent Non-Open Access. Molecules 2006, 11, 496–497, doi:10.3390/11070496.
  3. Lin, S.-K. Non-Open Access and Its Adverse Impact on Molecules. Molecules 2007, 12, 1436–1437, doi:10.3390/12071436.
  4. Lin, S.-K. Full Open Access Publishing Policy Imposed in 2007: Molecules Publishes Many More Papers This Year ― More than 2000 Pages Published up to Issue 8. Molecules 2007, 12, 2001–2002, doi:10.3390/12082001.
  5. Lin, S.-K.; McPhee, D.J. Citation of Two Retracted Papers Shows Both the Impact Advantage and an Unintended Consequence of Open Access. Molecules 2007, 12, 2190–2192, doi:10.3390/12092190.
  6. Lin, S.-K.; McPhee, D.J. Molecules' Highlights in 2008 and a Look Forward to 2009. Molecules 2009, 14, 584–585, doi:10.3390/molecules14010584.
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