Impact Factors

Journal Impact Factors: ‘Tis the Season

Marilyn H. Oermann

nurse author & Editor, 2014, 24(2), 6

Every few years I write an editorial or article about the impact factors (IFs) of nursing journals. This is the season for editorials on this topic because the new IFs will be released shortly. I typically weave in these papers the need for authors to select journals based on the purpose of the manuscript and audience to be reached rather than searching for a journal with an IF. However, I have not convinced enough readers of this basic principle—choose a journal for its relevance to your topic not its IF. When I give speeches on writing for publication, participants continue to report they were told by faculty and colleagues to publish in journals with an IF. I am hoping those faculty and colleagues are reading this editorial.

Journal Impact Factors:  What are they?

The journal IF is the frequency of citations to articles in an indexed journal during a set period of time. Only journals that are indexed in the Web of Science database receive an IF. While that database includes more than 12,000 journals, at the time this editorial was written, there were only 106 nursing journals with an IF (Thomas Reuters 2013a). This is a small number considering there are about 755 nursing journals in the Cumulative Index to Nursing and Allied Health Literature database (EBSCO Industries, Inc., 2012). The IF is a ratio:  the numerator is the number of current year citations in indexed journals to articles published by Journal X within the prior 2-year time period. That number is divided by the number of citable articles published in Journal X in the same time frame (the denominator). A 5-year IF also is available.

What should be clear from this equation is that the IF depends on which articles are identified as citable. When authors cite editorials, columns, commentaries, news items, and other similar types of papers in indexed journals, this helps the IF because those papers are not counted typically as citable items. For example, a nursing journal that includes a News section is not only good for keeping readers up-to-date, but it also can be good for the journal IF if cited because those News articles are not included in the number of citable items in the denominator.

What Characteristics of Articles Influence Impact Factors?

What else can influence a journal’s IF?  Journals that publish research papers and reviews typically have higher IFs because those articles are cited more frequently than other types of articles. Review papers in particular and articles with long reference lists are more likely to be cited (Althouse, West, Bergstrom & Bergstrom 2009, Neff & Olden 2010, Oermann & Shaw-Kokot 2013a). Some journals have restrictions on the length of papers and number of references with an article, which can affect their IFs.

One paper that is highly cited in a journal can skew the journal’s IF. An example of this was seen a few years ago when the IF of the journal Acta Crystallographica A increased from about 2.38 in the prior 4 years to 49.93 (Dimitrov, Kaveri & Bayry 2010). In 2009, Acta Crystallographica A had 5,966 citations to 72 articles published in 2008; none of the articles received more than 3 citations except for 1 article that had 5,624 citations to it, a number that has continued to increase since that time. The article was on the history of a computer program used for the refinement of crystal structures in chemistry.

Be Savvy about Nursing Journal Impact Factors

There have been many articles over the years about issues with IFs and the need to develop alternate ways of assessing research. The San Francisco Declaration on Research Assessment (DORA) includes 18 recommendations to improve the evaluation of the output of scientific research by funding agencies, academic institutions, and other parties (DORA 2013). However, it is unlikely that journal IFs will fade away, and for this reason editors and authors need to understand how IFs are calculated, what they mean, and how to interpret them. Alternatives to IFs have been the subject of many editorials, but there are issues with any metric especially when applied to various types of journals.

Last year I analyzed the IFs of the 5 nursing education journals that had them. This analysis allowed me to better interpret their IFs and gave me a good perspective, important at this time of the year when the new IFs will be released. The IFs of these nursing education journals are low when compared to biomedical journals, but my analysis showed they were comparable to many other nursing journals and to education journals in general. Two of the nursing education journals were higher than the median IF for journals in the Education (Scientific Disciplines) category, and the others were close to it (Oermann & Shaw-Kokot 2013b, Thomson Reuters 2013a). In the category Education and Educational Research with more than 200 journals indexed, all except one of the nursing education journals were above this median (Thomson Reuters, 2013b).

My main issue with IFs is they tell readers nothing about the quality of the work and its importance to readers. The journal IF does not reflect if articles led to new ideas and directions, or if they were used by readers to change their practices. As editors we have a responsibility to publish articles that meet our readers’ needs without worrying about IF. Many of us edit journals with readers who rarely publish themselves, but they may read one of our papers and use some of the concepts and ideas in the paper to improve their clinical or educational practices. The articles published in journals without IFs (most of the nursing journals) and with low IFs (many others) can have an important impact on readers and their practices no matter what area of nursing they are in.

This is the season for editorials on IFs—many are written following the release of the new IFs in mid-June. I wrote this editorial before the new IFs are released. This season, I am not worrying about IFs, and I hope other editors join me. I am keeping a good perspective of what they mean and do not mean.


  • Althouse, B. M., West, J. D., Bergstrom, T., & Bergstrom C. T. (2009). Differences in impact factor across fields and over time. Journal of the American Society for Information Science and Technology, 60(1), 27-34.
  • Dimitrov, J. D., Kaveri, S. V., & Bayry, J. (2010). Metrics: journal’s impact factor skewed by a single paper. Nature, 466(7303), 179.
  • EBSCO Industries, Inc. (2012). Cumulative Index to Nursing and Allied Health Literature.
  • Neff, B. D. & Olden, J. D. (2010). Not so fast: Inflation in impact factors contributes to
    apparent improvements in journal quality. BioScience, 60, 455-459.
  • Oermann, M. H., & Shaw-Kokot, J. (2013a). Impact factors of nursing journals:  What nurses need to know. Journal of Continuing Education in Nursing, 44, 293-301.
  • Oermann, M. H., & Shaw-Kokot, J. (2013b). Addressing the impact factors of nursing education journals. Journal of Nursing Education, 52, 483-484.
  • San Francisco Declaration on Research Assessment. Putting science into the assessment of research. 2012.
  • Thomson Reuters. (2013a). Journal Citation Reports. 2011 JCR Science Edition. New York, NY: Thomson Reuters.
  • Thomson Reuters. (2013b). Journal Citation Reports. 2011 JCR Social Science Edition. New York, NY: Thomson Reuters.

about the author

Marilyn H. Oermann, PhD, RN, ANEF, FAAN, is Thelma M. Ingles Professor of Nursing and Director of Evaluation and Educational Research, Duke University School of Nursing, Durham, North Carolina, USA. She is the Editor-in-Chief of Nurse Educator and the Journal of Nursing Care Quality. Her email is

NAE 2014 24 2 6 Oermann

Copyright 2014: The Author. May not be reproduced without permission.
Journal Complication Copyright 2014: John Wiley and Sons Ltd