The journal impact factor (JIF) and how best to rate the performance of an academic using the h-index were topics in two recent editorials (Jackson et al. 2009, Thompson & Watson 2009). The Hirsch (2005)h-index is becoming widely accepted to assess a researcher’s scientific output (Cronin & Meho 2006) and can be easily obtained using popular electronic databases such as Web of Science (WoS), Scopus and Google Scholar (Bakkalbasi et al. 2006). The h-index combines quantity (number of publications) and impact (number of citations) and can be calculated for an individual, a group of researchers or journal (Schubert & Glanzel 2007, Vinkler 2007). In this editorial, we expand on the two previous ones by examining JIFs of the top 12 nursing journals and the corresponding number of citations accrued since 1995. In addition, we examine the current standing of nursing journals within the competitive citation stakes to that of other medical specialities, which show that editors and researchers in nursing need to ‘lift their game’ to remain competitive to publish high quality papers. In the long run, quality is better than quantity when it comes time to assess a person’s academic performance for grants, tenure or promotion.
Table 1 lists the top 12 nursing journals ranked by their 2008 ISI impact factor, the number of articles published since 1995 and accrued citations to 2009. The WoS database was used to construct the table excluding editorial material, letters to the editor, abstracts, book reviews and other non-citable material. Closer inspection of the table shows that in this data set, the Journal of Advanced Nursing published the most articles (4328) and had the highest h-index of 52: e.g., at least 52 articles had 52 or more citations. JCN published the second highest number of articles (2217) and achieved an h-index of 30.
|Rank WoS||Journal||JIF (2008)||Number of articles (1995–2009)||h-index||Mean citations per item||% with ≥ 50 citations||% with ≥ 30 citations|
|1||Birth-Issues Perinatal Care||2·836||482||35||11·38||2·1||10·2|
|2||Inter J Nursing Studies||2·310||1256||27||6·08||0·4||1·6|
|3||Oncology Nursing Forum||2·207||444*||18||4·07||0||0·7|
|4||Am J Critical Care||2·043||436†||21||4·93||0·3||1·4|
|6||J Advanced Nursing||1·654||4328||52||10·26||1·5||5·9|
|8||Pain Management Nursing||1·537||87‡||7||2·17||0||1·1|
|9||J Cardiovascular Nursing||1·471||249‡||10||2·13||0||0|
|10||Res Nursing & Health||1·457||715||39||12·01||2·9||8·8|
|11||Biological Research Nursing||1·386||148§||7||1·86||0||0|
|12||J Clinical Nursing||1·376||2217||30||5·03||0·2||1·5|
Articles that accrue 30 or 50 citations are essential to a researcher’s academic career as they are likely to be included in the most productive core of an author’s output, referred to as the Hirsch-core (h-core). In certain fields of research, those with an h-index of 40-60 indicate outstanding achievement, and those with an h-index of 20 indicate a ‘successful scientist’ (Hirsch 2005). Thus, Table 1 also shows the percentage of papers that received at least 30 or 50+ citations for each journal. Overall, one can see that a very few articles (< 5%) achieved 50+ citations, and there is a wide variation in proportion that received 30 or more citations (0–10%). This is not to say that highly cited papers are exempt from nursing journals. For example, an article by Sandelowski (2000) received the highest number of citations (321) for this analysis, and 22 other articles were cited 100 or more times. Thus, editors need to remember that authors aspire to have their articles gain wide exposure and become highly cited, whilst they may favour papers they think will contribute to the two-year citation window used to calculate the journal’s impact factor.
Differences in the h-index exist between disciplines and specialty areas that need to be considered when assessing the performance of researchers or journal impact (Althouse et al. 2009, Johnstone 2007). Table 2 shows that, compared with other speciality areas in medicine and allied health, nursing journals have the lowest ranking based on median impact factor. It should also be noted that the highest JIF for the 62 nursing journals in the WoS data set is currently 2·836, whereas all other sets have many journals with higher impact factors. Obviously, there is a steep road to climb for nursing journals to reach the higher tiers of the impact factor ladder.
|Journal category||Number of Journals||Number of articles*||Total cites||Median impact factor||JIF distribution|
|≥ 5·0||3·0–4·9||2·0–2·9||1·0–1·9||< 1·0|
|Psychiatry||101||10 822||466 932||2·318||8||28||26||16||23|
|Critical Care Medicine||21||3636||141 146||2·154||3||3||6||7||2|
|Geriatrics & Gerontology||36||3000||89 810||2·065||5||9||6||9||7|
|Clinical Neurology||156||19 782||680 449||2·050||15||27||38||48||27|
|Urology & Nephrology||57||9459||273 655||1·937||5||8||15||18||11|
|Nutrition & Dietetics||59||7101||216 926||1·888||3||10||14||16||16|
|Public, Environ & Occupat Health||105||11 491||364 293||1·787||7||12||27||36||23|
|Obstetrics & Gynaecology||61||8658||226 595||1·757||1||9||16||25||10|
|Health Care Sci & Services||62||4564||101 797||1·490||1||6||14||27||14|
|Tropical Medicine||15||2023||41 584||1·450||0||1||4||4||6|
|Surgery||148||26 094||731 229||1·369||3||13||22||51||53|
|Emergency Medicine||13||1836||34 077||1·188||0||1||2||4||6|
In a recent study, we compared the JIF and h-index for psychiatric journals and demonstrated there were strong positive correlations between JIF, average cites per article and the h-index for papers published in psychiatric journals in 1995–1999 and 2000–2005 (Hunt et al. 2010). Previous studies have reported strong correlations between JIF and the h-index for science journals using a two-year window (Schubert & Glanzel 2007). Whilst the h-index ignores JIF, they are not unrelated, and the high correlation is likely owing to the ability of highly ranked journals and editors to attract the best available papers.
Finally, citations are not the ‘be all and end all’ of an article’s publication success. If an article is not cited, this does not mean that it is not read or used for clinical or education purposes. Excellent papers without high citation rates are used for health policy, training purposes or to communicate important issues to journal readers. Furthermore, negative reasons may also account for high citation rates such as flawed methodology. Particular types of articles such as reviews may attract more citations than other (Bornmann & Daniel 2008). It is also worth noting that many well-regarded journals do not receive an impact factor directly from the ISI Journal Citation Reports. As shown in Table 1, the h-index of a journal is a different way to rank journals, which does not rely on Journal Citation Reports. That said, the h-index is relatively easy to calculate and given the current mantra of ‘be cited or perish’ (Garfield 1996, Walter 2002), its strengths and limitations are worth knowing about (Jacso 2008, Bornmann & Daniel 2009, Hunt et al. 2010).