Two-year citations of JAPPL original articles: evidence of a relative age effect

Abstract

Several indicators have been used to analyze scientific journals, with the impact factor and the number of citations in a 2-yr calendar time frame (2-YRC) being the most common factors. However, considering that the Journal of Applied Physiology (JAPPL) appears monthly and that calculations of these indicators are based on citations of papers published in previous years, we hypothesized that articles published at the beginning of the year would be cited more in the 2-YRC compared with those appearing in the last issues of the year, a phenomena known as a relative age effect. Our objective was to confirm the existence of a relative age effect in the 2-YRC for original articles published in JAPPL. From 2005 to 2008, a total of 1,726 original articles were published, according to the Web of Science, and 9,973 citations in 2-YRC, varying from 0 to 45, with a mean of 5.78 for individual papers. Although there were no differences in the number of original articles published in a given month (P = 0.99), the 2-YRC varied considerably throughout the year, being higher for those earlier issues of the year, as shown by the linear regression analysis (r(2) = 0.76; P < 0.001). The 2-YRC began at 6.62 during the first 3 mo of the year, dropping by 10% at each 3-mo period. In summary, the longer an article has been out there, the more citations it collects. The relative age effect is a potential confounding variable for the assessment and interpretation of 2-YRC (using calendar years) from JAPPL original articles.

Why Do Some Articles in Planning Journals Get Cited More than Others?

“… 3. Ayres and Vars (2000); Bornmann and Williams (2013); De Araujo et al (2012); Filion and Pless (2008); Frosch et al (2010); Gargouri et al (2010); Georgas and Cullars (2005); Guerrero-Bote and Moya-Anegón (2014). …”

No evidence of citation bias as a determinant of STEM gender disparities in US biochemistry, genetics and molecular biology research

“…The US has been the major single contributor to this Scopus category. Articles published 2015-18 were excluded from the citation analysis component because several years are needed for citation counts to stabilise and shrink within-year citation differentials (de Araújo, de Oliveira, de Oliveira Brito, et al, 2012). First and last author genders were detected using a list of gendered first names that has an error rate of 1.5% on US academics but leaves some genders unknown and overestimates the proportion of females by 1% (based on comparisons with human-checked data in: Thelwall et al, 2019).…”

Effects of aging, and other bad behaviors

“…Within-journal variance in citation numbers across the spectrum of published articles is a further limitation to use of the impact factor, and that is the subject of this editorial. In this issue of the Journal of Applied Physiology, an analysis of one cause of within-journal citation variance is presented by Araujo et al (1). This is the "aging effect."…”

“…With the impact factor being a number based on average citations to papers published over 12 calendar months, the authors showed that those papers published early in the calendar year receive more citations than those published later in the year. Linear regression of their data (1) shows the decrease in citations is linear month by month from a high of 6.7 in January to a low of 4.8 in December. The reason given is that the longer a paper has been in print, the more likely it is to have garnered citations, all other factors equal.…”

“…If one now examines all of the 747 articles (512 research articles, plus 235 editorials, reviews, point:counterpoint debates, viewpoints, and letters) published in the Journal of Applied Physiology in 2007 [one of the years covered by the analysis of Araujo et al (1)], the frequency distribution of citations to each paper is astonishing, as shown in Fig. 1.…”