Q&A II: Published Papers

Here is the second post in our series responding to questions from authors, editors and readers of MDPI journals, all raised during open access week. If you have further feedback or questions you would like to share with us, you can do so at anytime by visiting our Feedback Corner. The following covers questions about published papers.


Q. Are there any limitations on the length of a paper?

A. No, as we publish online only there are no limitations. However, be aware that it can be more difficult to find reviewers for long papers and the processing time might, therefore, be longer.



Q. Does every published paper have a doi number?

A. Yes, MDPI is a member of Crossref, which issues digital object identifier (doi) numbers. This is a number that acts as a unique reference to a paper and is used by indexing databases and similar services. Every paper published by MDPI has a doi number. In general, we would recommend scholars against submitting to journals that don’t assign doi numbers.



Q. Is there any difference between special issue papers and regular papers?

A. Special issue papers are part of a collection of papers on a similar theme, managed by an invited Guest Editor. All papers from a special issue are shown together on the special issue webpage. However, every paper is published shortly after it is accepted—we don’t wait for all papers in a special issue to have a final decision before publishing them—so special issue papers also appear as part of the regular issue.



Q. Can I volunteer to review for an MDPI journal?

A. Yes! Read the information at https://www.mdpi.com/reviewers and register at https://susy.mdpi.com/volunteer_reviewer/step/1. The Managing Editor will assess your suitability as a reviewer and inform you of a decision within a few days.



Q. Where can authors submit a proposal for a special issue paper?

A. We welcome proposals for special issue papers and are happy to check suitability in advance, although we cannot offer a guarantee that the final paper will be published. Authors can submit proposals directly to the Managing Editor at the editorial office of the appropriate journal. Contact details are on the journal website. We also welcome proposals for special issues from potential guest editors. If you have a topic that you think would be of interest to readers of the journal, please contact the editorial office.

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