In 2005 and 2006 papers were published in MDPI journals in both non-Open Access (non-OA) and Open Access (OA) form. In 2005, 70 papers (just under 50% of the total) were published in the password protected (non-Open Access) area of Molecules. Not unexpectedly, this reduced number of Open Access papers had a significant influence on the impact factor of Molecules, which was reduced from 1.113 in 2005 to 0.841 in 2006....
Like Molecules, in 2005 another MDPI journal, International Journal of Molecular Sciences, also published a significant percentage of papers in its password protected (non-Open Access) area. The impact factor of International Journal of Molecular Sciences was also reduced from 1.467 in 2005 to 0.679 in 2006....
As shown in Tables 1 and 2 [showing article, citation, and OA status data for the two journals], the non-Open Access papers and their obviously lower citation numbers appear to be the main reason behind the reduced impact factors of these two journals, where almost half of the papers published were in non-OA form....
As a contrast, the MDPI journal Sensors published only a very small number of non-Open Access papers in 2005, and its impact factor increased slightly from 1.208 in 2005 to 1.373 in 2006.
Since April 2007, we have granted full Open Access to all the papers published in all MDPI journals in 2005 and 2006, and in 2007, we have published papers exclusively in Open Access form. We expect this will be reflected in an increase in impact factors come the next evaluation.
Peter Suber at 7/21/2007 10:04:00 AM.
The open access movement:
Putting peer-reviewed scientific and scholarly literature
on the internet. Making it available free of charge and
free of most copyright and licensing restrictions.
Removing the barriers to serious research.