Medicine vs. Surgery – Citation and Publication Trends


So, which discipline does get the most scholarly attention? 

Surgical journals publish almost twice as many articles as Medical journals

Based on the way ISI classifies journals, there have consistently been more scholarly publications on the topic of Surgery than there were on the topic of Medicine (either general medical articles or internal medicine). 

This does not cover other medical publications categorized under medical specialties, such as Oncology, Anesthesiology or Pediatrics.  (To see an analysis of these medical categories for 2009, please see the article “Medical Sciences – Research and Impact Analysis”.)

While the Surgery category is an average 30% larger than its Medical counterpart in terms of journals, these Surgery journals publish almost twice as many articles as the Medical category.

Medicine outperforms Surgery in citations

But while there is quite a bit more activity coming from Surgery than Medicine, the citations have traditionally favored the Medical journals.

When looking at average citations per journal, the Medicine category has almost doubled the rate of the Surgical journals, although in 2009 the variance is much less.

When we factor in the number of items published vs. the number of citations for each category, the discrepancy widens even more.   During all of the past 10 years, the subject category Medicine received on average more than double the number of citations per article the Surgery category did.

<Note:> Citations per article metric means # citations received in current year divided by # articles published in current year.

                   

  

 

 
 
 

 

 

Surgery outperforms Medicine in Cited Half-Life, while Medicine wins in Immediacy

Citation Longevity tells us how long citations remain relevant.  As we know, the majority of the scientific community, whether publishers, institutions or researchers, looks primarily at Impact Factor, which we will look at shortly.  But Impact Factor just covers a short period of time.Cited Half-Life of a journal tells us the median age of articles being cited.  A journal’s 2009 Cited Half-Life would be the median age of articles being cited in 2009.  (Note that ISI only tracks to a maximum Cited Half-Life of “10+ years”.)  In the case of Medicine vs Surgery, we see that Surgery has a slight historic edge, beating out Medicine by a range of 10-20%.  In 2009, Surgery had a 10% edge, with articles 7.2 years old or older receiving half of 2009’s cited references, while Medicine saw a Cited Half-Life of 6.5 years.

The Immediacy Index shows us how quickly articles are being cited.  A journal’s 2009 Immediacy Index is the average number of citations a journal is receiving within year of publication.  And as we see from the above, Medicine routinely outperforms Surgery in Immediacy – at a rate of almost 4 to 1 in places.  In 2009, Medicine had almost a 3:1 advantage in Immediacy, with medical journals receiving an average of 0.75 citations per article in 2009, while surgical journals received an average of 0.27 citations per article.  So, essentially, 3 out of 4 medical articles published in 2009 received a citation in 2009, while only 1 out of 4 surgical articles received a citation in that same year.  And 2009 saw the least variance between the two categories.

Medicine has a much larger range of Impact Factors than Surgery

 The Annals of Surgery is 2009’s Impact Factor winner for the Surgery category, with an Impact Factor of 7.900.  Other notables include AM J TRANSPLANT, BRIT J SURGERY and ENDOSCOPY in recent years.  But Medicine has routinely outperformed Surgery in area of Impact Factor, with 8 journals receiving a higher IF than Surgery’s 2009 winner.

With a 2009 Impact Factor of 47.050, the New England Journal of Medicine clearly has the highest Impact Factor, as it has for the past nine years.  NEJM is followed by LANCET and JAMA (the Journal of the American Medical Association) with respective Impact Factors of 30.758 and 28.899.  This means that for these three journals alone, during 2009 they received over 100 citations for every article published during 2007-2008.

It should come as no surprise that the Medicine category has a much higher average Impact Factor than the Surgery category as a whole.

Average journal IF has diverged over the years

While the two categories started the 21st Century reasonably close in terms of average IF, the two categories have seen a large divergence in the latter part of the decade.  Although the two finished reasonably close in 2009, with an average IF variance of 62%, the average Medicine IF in 2008 was double that of the average Surgery journal.

<Note:>  The Impact Factor is a generally accepted metric conveying influence within the scholarly community.  The Impact Factor shows how many citations occurred during a given year as compared with the total number of articles in the previous two years.

Based on the analyses we have seen thus far, we can feel pretty confident to say that Medical journals, as a whole, are receiving more scholarly citations (and therefore having a greater impact) than journals classified under the Surgery category.  We can also say that while the trend has been increasingly disparate, 2009 seemed counter to trends, with IF and other key metrics demonstrating less of a disparity in 2009 than in prior years.

Medicine sees higher quality citations, over time, than Surgery

Eigenfactor.com has published a couple of additional metrics, covered in ISI’s Journal Citation Reports, which speak to the quality of citations being received.  There is the Eigenfactor Score, which looks at multiple generations of citations, and Article Influence, which conveys the relative quality of citations, with higher scores going to articles receiving citations from other higher scoring articles.

ISI has only been tracking Eigenfactor metrics for three years, but we see a definite pattern – that Medical journals receive a better quality of citations than the Surgical journals.  That being said, in 2009 Medicine’s average Eigenfactor Score did drop as compared with previous performance.

Unfortunately, there is no one metric which can tell us everything we need or want to know about a journal.  The Impact Factor is a useful metric, but it really only covers a limited period of time.  The Eigenfactor is useful as well, but is limited in scope (not all journals have Eigenfactor scores, and those which do are only available for three years of data).  Citations per article would be great if it could refer to an entire body of work instead of “current year” publication, which can vary over time.

Medicinal journals consistently outperform Surgical journals in three key metrics

But I have combined these three metrics, to show how consistently strong Medicine is when compared against Surgery.  In looking at all of the journals covered in 2009, the majority have low Eigenfactor scores, even those ranging to an Impact Factor of 10.0.  But several Medical journals stand out, clearly receiving high volumes of citations per article, high Eigenfactor scores and high Impact Factors.  These top Medical journals are those with the highest Impact Factors:

  1. NEW ENGL J MED
  2. LANCET
  3. JAMA-J AM MED ASSOC
  4. ANN INTERN MED
  5. BRIT MED J
  6. PLOS MED
  7. ANNU REV MED
  8. ARCH INTERN MED

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The above analysis is based on data from ISI (The Institute for Scientific Information), a Thomson Reuters company.  Data was taken from the JCR (Journal Citation Reports) 2001-2009, and all categorization is using the ISI categories.

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Comments
2 Responses to “Medicine vs. Surgery – Citation and Publication Trends”
  1. Neal Fisher says:

    Wow, very through and informative article, and a good Scrubs clip!

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