JCR (journal citation report) impact factor (IF) is considered a standard quantitative tool designed to evaluate and compare the quality of scientific journals (Clarivate, 2021a). IF is estimated by the ratio of total citations received by a journal in a given year to the number of citable articles published in two previous years (Calculator Academy Team, 2021). Unlike IF, other bibliometrics such as the Eigenfactor score weighs citations depending on citing journal's ranking (EIGENFACTOR.org), while source normalized impact per paper (SNIP) score is adjusted to the variations among the different scientific fields (Elsevier, 2012). Moreover, Eigenfactor and SNIP incorporate data over the last five and three years, respectively.

The value and misuse of IF has been under scrutiny for several years (Bornmann et al., 2012). Readers often select an article based on the number of citations it has received and the prestige of the publishing journal (Lemke et al., 2021). Brown and Gutman compared the bibliometrics of occupational journals and concluded that metrics such as Eigenfactor, SNIP, and Scimago journal ranking should be used in addition to IF to evaluate journals' quality (Brown and Gutman, 2018). However, most of the research on bibliometrics was conducted prior to the COVID-19 outbreak (Kianifar et al., 2014; Yuen, 2018). The latest JCR was published in June 2021, based on the 2020 data, and defined an unprecedented upsurge in pediatric and other biomedical journals' IF. Several publishers have been avidly marketing this report (EDP Sciences, 2021; ESA, 2021; Weingarden, 2021). Since the number of citations determines the IF, a sharp increase in publication volume during the COVID-19 outbreak possibly led to an upsurge in the citations offered to the biomedical journals (Aviv-Reuven and Rosenfeld, 2021). Between 2012 and 2019, the number of open access (OA) journal publications had increased considerably from one to four million articles, influencing citation volumes (Morrison, 2021). However, comparative analysis between OA and subscription biomedical journals' recent trends has not been reported.

We conducted a cross-sectional study to estimate IF and other bibliometrics (IF ranking, Eigenfactor, and SNIP) of pediatric journals between 2018 and 2020 and compared the rate of changes in the bibliometrics between 2020 and 2019. The secondary objectives of our study were to compare the growth of biomedical journals in 2020 with the previous years and estimate the difference between OA and subscription journals' trends. Finally, we analyzed IF changes among the journals of a different specialty, pulmonology, to understand whether IF upsurge was specific to the field of pediatrics or a general trend.

This cross-sectional study demonstrated a sudden uptrend in IFs of pediatric journals in 2020 compared to 2019. In contrast, other bibliometrics including IF ranking and Eigenfactor scores, were relatively stable within that time interval. IF and Eigenfactor also did not change meaningfully between 2018 and 2019. However, SNIP scores of pediatric journals progressively increased from 2018 to 2020. We also determined that the uptrend in IF was not limited to the top-ranked pediatric journals; instead, the phenomenon was universally observed irrespective of journals' ranking. A similar trend was also observed in other biomedical fields beyond pediatrics. The scientific community entrusts IF as a reliable tool to estimate journals' significance, and the sudden uptrend might have conveyed biased messages.

Merits of IF and Eigenfactor have been compared in the past. Eigenfactor is an efficient scientific metric since it is also adjusted for citing journals' quality. Journal rankings often change depending on whether IF or Eigenfactor were used (Rizkallah and Sin, 2010), indicating that journals should not be evaluated based on a single metric. Additionally, our study demonstrated an advantage of the Eigenfactor because of its ability to resist year-to-year variation due to increased publication volume. SNIP, designed by Scopus, was primarily intended to adjust for the variation in citation patterns among different scientific fields (Leydesdorff and Opthof, 2010). However, we found that SNIP also became vulnerable like IF to the sudden upsurge in publication numbers.

A considerably higher volume of biomedical articles and references were published in 2020 compared to 2019, which perhaps prompted the upsurge of IFs across the various fields of biomedical sciences (Figure 1). The rationale behind increased publication volumes in 2020 was beyond the scope of this study. However, it might be related to markedly escalated research productivity since the COVID-19 outbreak (Nigrovic and Napper, 2021). Both OA and subscription journals experienced a considerable increase in publication volume in 2020. However, the OA journals perhaps were more lenient with acceptance due to lack of space constraints and experienced a higher growth rate than the subscription journals.

Our study has several limitations. This project focused solely on citation counts and not how the journals could influence the IF. For example, some journals no longer publish case reports as those types of articles would count toward the citable papers but are infrequently referenced (Rison et al., 2017). Journals may also prefer to accept reviews (more often cited) or publicize aggressively in social media. Second, we considered all biomedical journals as the source of citations for pediatric journals, which could be an overgeneralization. Moreover, traditional subscription journals often publish few OA articles, as several publishers have been leaning toward a hybrid model in recent years (Pinfield et al., 2017). Thus, OA vs. subscription journal classification could be an oversimplification. Nonetheless, this study has few strengths. To the best of our knowledge, no previous study reported the sudden uptrend in IF since the outbreak of COVID-19. Our study showed that increased IF affected not only all tires of pediatric journals but other specialties too. Henceforth, it is likely to be a general phenomenon. Finally, we analyzed other bibliometrics in addition to IF and found that Eigenfactor scores were more stable than IF.

A significant upsurge in pediatric journals' IF in 2020 was perhaps related to the sudden increase in overall publication volumes since the COVID-19 outbreak. Due to its vulnerability, IF should be cautiously reported as a benchmark of excellence. Unlike IF, Eigenfactor scores of pediatric journals remained unchanged in 2020, citing an additional advantage of Eigenfactor compared to other bibliometrics. A similar trend in IF was observed among all quartiles of pediatric journals, irrespective of quality and prestige. A similar uptrend in IF was also observed in journals of another specialty such as pulmonology. Both OA and subscription journals experienced a considerable increase in publication volume in 2020. However, the OA journals experienced even higher growth than the subscription journals.

The data will be made available upon request.

PM conceptualized, designed the study, supervised data collection, analyses, drafted the initial manuscript, reviewed, and revised the manuscript. LM, LS, and SG conceptualized, designed the data collection instruments, collected data, conducted initial analyses, reviewed, and revised the manuscript. ED conceptualized the study, supervised various aspects of accessing the data, and critically reviewed the manuscript for important intellectual content. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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