Is Your Journal Indexed in MEDLINE?

1) Scope and Coverage.

Articles must deal with biomedical subjects. The committee will, however, consider non-biomedical journals occasionally if they are thought to significantly contribute to the medical and allied sciences.

2) Quality and Content.

The most important aspect of any journal is its scientific merit (validity, importance, and degree of contributions to the biomedical sciences).

3) Quality of Editorial Work.

The quality of the editorial work must reflect objectivity, credibility, and quality. The committee carefully evaluates the external peer-review process, adherence to ethical guidelines, disclosure of conflicts of interest, timely publication of errata, responsible retractions when appropriate, and opportunity for the expression of dissenting opinions.

4) Lack of Commercial Influence.

The committee specifically assesses the potential influence that any advertising or commercial activities may have on the quality of the articles published.

5) Production Quality.

The layout, printing, graphics, and illustrations are all taken into account. A journal printed on acid-free paper (as the American Journal of Neuroradiology [AJNR] is) receives higher evaluation scores.

6) Audience.

Journals must be geared toward audiences comprising health professionals at every level (physicians, researchers, administrators, etc).

7) Types of Content.

Content of a journal must include 1 or more of the following: original research, clinical observations, reviews, statistical compilations, case reports, and varying analysis (philosophic, ethical, social, etc). Publications consisting mainly of previously published articles (such as our Special Collections) or only abstracts (such as meeting program syllabi) are not considered for inclusion in MEDLINE.

8) Journals in Languages other than English.

These are considered as long as the abstracts are in English and they meet the same criteria as their English counterparts.

9) Geographic Coverage.

Journals are selected independent of where they are published. They should provide wide international coverage.

10) Journal Categories.

All of the above criteria are influenced by the main purpose of a journal. Journals fall into the following categories:

1. Research: those that report original investigations.

2. Clinical or Practice: those that contain information regarding the current state of medical practice.

3. Review: those that provide background information of accepted principles in a consensus fashion.

4. General or All-Purpose: those geared toward broad audiences that contain elements of A−C.

After evaluation, journals are graded on a 0- to 5-point scale and about 25% of those reviewed will be accepted for indexing in MEDLINE. Only those receiving scores of 3.75 or higher are selected. If acceptance is denied, one may appeal the decision or decide to reapply 2 years later. Subsequent reviews are done on a 3-year basis. If a journal is less than 3 years old, it will be indexed entirely at the time of selection; if it is older than 4 years, indexing begins with the most recent year. A change in the title of a journal necessitates undergoing a new application. The merger of an indexed journal with one that is not indexed also requires a new application. Journals are audited periodically, and major changes for the worse may result in loss of their indexing.

Of course, because less than 50% of all biomedical publications are listed on MEDLINE, there are other data bases. This commentary would not be complete without mention of some of these. The Embase data base (owned by Elsevier) contains about 1800 journal titles not found in MEDLINE (for a total of approximately 7000) and about 20 million individual entries.⁴ The benefit of using Embase is wider coverage and inclusion of extensive pharmacologic and drug-related literature. Most medical school libraries that I know subscribe to this fee-for-service activity. Elsevier also owns the FIRST Consult data base.⁵ This data base is divided into 3 parts: medical topics (apparently those related to evidence-based medicine), differential diagnosis, and a guide to procedures. It contains an index to all articles published in the Clinics series. Another important data base owned by Elsevier is Scopus.⁶ This data base covers articles and abstracts from more than 16,500 journals extending beyond the biomedical sciences. The interesting thing about Scopus is that it contains author information including bibliography, citation rates, affiliations, etc.

There are other data bases that deal mostly with drugs, natural medicine, sports-related diseases, and psychiatric illnesses that are of no or little interest to neuroradiologists and are not addressed here. The Web of Science data base (owned by Thomson Reuters) is of interest mostly to editors and those in related occupations (it is also used by some promotions committees).⁷ It contains information on more than 10,000 highly rated journals and expands to the social sciences, humanities, and arts. This powerful data base allows in-depth analysis of the performance of a journal and individual authors. The Journal Citation Reports data base is part of the Web of Science (it contains the famous “Impact Factor”). These are also paid services and are generally available through most medical school libraries.

The main difference between MEDLINE and the above-mentioned data bases is that journals included in them generally do not undergo rigorous evaluation. For example, Embase requires filling out a simple form suggesting the title you want included there. Their Web site provides no details as to who reviews the applications or the process. For Scopus, the title to be included is evaluated by a committee formed by “approximately 20 scientists and 10 librarians from all corners of the world,” but further details are not given on that Web site. Content (either partial or full) from AJNR is found in all of these data bases.

Now I want to touch on Google Scholar. This is a subset of Google Web Search that permits searching of the academic literature, including articles, theses, books, and reports, so it is much more comprehensive than all other data bases. Google Scholar often links you to the article you are looking for via the Web site of the commercial publisher (these, in turn, may be linked to your medical school library, and you should not have to pay for most articles). The problem with Google Scholar, paradoxically, is its comprehensiveness. Because all references appear in a search, one must be careful to select only those items that seem reliable, relevant, timely, and valid. This search engine can also look for legal opinions and patents. Google Scholar is still considered to be in its “beta” testing stage and what the final product will be able to do and look like, no one is certain. At this time, some academic libraries use Google Scholar as one of their search engines. Google Scholar sends “crawlers” into Web sites to learn their content, and some sites do not allow it. Listings of articles published in journals owned by Elsevier may be limited because this publisher did not allow entry of Google crawlers before 2007. More important, Google Scholar often displays only the first and last authors. Because Google Scholar registers all activities related to publications, it may become the most important scientific search engine in the future.

To end, a few words about Index Medicus. The Index was started in 1879 as a comprehensive list of medical science articles and was last published in 2004. Throughout its history, it assumed different configurations and was published by the National Library of Medicine or the American Medical Association. All data contained in it can now be found on MEDLINE and are accessible via PubMed.⁸ Inclusion of a journal in the Index was subject to the same requirements as MEDLINE. Many of us still remember using the hefty Cumulated Index Medicus books to look for references. What a relief to be able to do it from our computers!

I think our readers and contributors can be confident that AJNR meets all criteria put forth by all data bases mentioned and can be found there. As criteria change, we will too, assuring that AJNR maintains its preeminent position in the clinical neurosciences.