Editor's note (7th April 2022) : Wiley Journal Insights bibliometrics reporting already reflects this change. This means that any metrics referencing 2020 onwards, specifically citations and research output, will be based on the Early Access year where available (and Issue Cover year where there is no Early Access data available). As a result, you will see a redistribution of papers and citations over time, together with a general increase in citations and papers published after 2020.

Over the past few months, Clarivate have published several blog posts announcing their plans for the inclusion of Early Access content in the Journal Citation Reports (JCR). Editors will be interested in the effect on how journals’ Impact Factors are calculated. At Wiley, we refer to Early Access content as EarlyView, which means online publication before a paper is assigned to an issue. In this post, I outline what is going to happen, and what it may mean for your journals.

In their blog post of 26th October 2020, Clarivate confirmed that they plan to introduce Early Access content to the 2021 edition of the JCR in a ‘phased manner’.

On 24th November 2020, Clarivate also defined what is meant by ‘a phased manner’, explaining their rationale in a further post on 28th January 2021.

Key points:

• The JCR will start including Early Access data this year (2021 release / 2020 metrics).
• Clarivate will use a ‘phased approach’ to introducing the data.
• All data elements referencing the year 2020 (i.e. cites made in 2020, papers published in 2020) onwards will be based on the Early Access year where available (and Issue Cover year where there is no Early Access data available).
• All data elements referencing years prior to 2020 will be based on Issue Cover year.
• Clarivate’s ‘phased approach’ may cause a temporary boost in Impact Factors (followed by a return to the previous trend). Initial estimates suggest that the boost may be up to 12%, but this may be inflated due to the faster indexing of Early Access content. This boost is unlikely to be maintained, so it is very possible that many journals will see a decrease in Impact Factors in subsequent years.
• We will continue to monitor the likely impact as the JCR data window draws to a close. Please speak to your Wiley Journal Publishing Manager with any questions.

A Phased Manner

Why is a phased approach necessary?

Clarivate have been experimenting with an Early Access data feed from publishers since 2017, however not all titles operate an Early Access system, and most titles able to supply Early Access information only had their feed switched on in July 2019. This means that prior to 2020, these titles only had partial Early Access publication date information for 2019, and nothing at all for prior years.

(Data pulled from Wiley’s licensed extract of data from Clarivate’s Web of Science product (SCI-E, SSCI, AHCI, ESCI) on 30th November 2020).

This would give the undesirable result of a single data year (2019) for a single publication being comprised of two different definitions of ‘year’ – half by Issue Cover year, half by Early Access year. This would be particularly problematic for journals with a small number of issues per year.

When the plan to include Early Access data in the JCR was first announced, we had assumed that it would not take place for a couple more years, and that when it switched, all citations and published articles would be listed according to their Early Access year (if present). Instead, Clarivate have opted for an earlier roll-out, with the Early Access information coming into the JCR in stages by year.

What will happen in the 2021 JCR release?

For the 2021 release of the JCR (containing 2020 Impact Factors), only 2020 data will be affected by the change to the Early Access year.

This means that the citations in the Impact Factor numerator will include citations made by Early Access papers, and will be drawn from citing articles with the Early Access publication year of 2020 (or Issue Cover year 2020, where Early Access year is not available). Similarly, the denominator of the Immediacy Index will be based on the Early Access publication year (or Issue Cover year where Early Access year is not available). Content from previous years will be listed according to Issue Cover year.

Some worked examples are available in the appendix at the end of this article.

The implications for Impact Factors

This ‘phased approach’ will almost certainly yield a temporary boost in journal Impact Factors across the JCR, since the numerator will include citations from Early Access articles while Early Access articles remain excluded from the denominator. This boost will be compounded by the fact that for this first year, citations with an Early Access year of 2019 and an Issue Cover year of 2020 (which would not have counted in the 2019 Impact Factor numerator) will be included in the 2020 Impact Factor numerator as 2020 citations.

(Data pulled from Wiley’s licensed extract of data from Clarivate’s Web of Science product (SCI-E, SSCI, AHCI, ESCI) on 3rd December 2020). We estimate a 3% boost to the 2020 IF citation pool as a result of including content with an Early Access year of 2019.

Another point of distortion is the change in the length of the citation window, being measured between the Issue Cover date of the cited paper and the Early Access date of the citing paper – effectively shortening the amount of time that articles have to be read, digested and cited in ongoing research. This distortion may be mild for titles that already use Early Access (the previous ‘Early Access citation benefit’ they might have seen will now be a normal part of the calculation), but titles that do not use Early Access may face a slight penalty.

Current models suggest that the overall pool of citations included in the 2020 Impact Factor will increase by c. 11%; 8% as a result of including citations made by Early Access papers, and a further 3% from the one-off inclusion of cites made by 2019 Early Access articles with an issue date of 2020. However, this early estimate is based on incomplete data, and may be in part the result of faster indexing of Early Access papers (compared to in-issue content). This means that the data lag normally seen in the run-up to the March JCR data extraction (caused by the supply of late-published issues and an inevitable indexing backlog at Clarivate) is reduced.

If you have any questions or concerns about how these changes may affect your journal’s Impact Factor, please speak to your Journal Publishing Manager.

Appendix: Worked examples

2019 Impact Factor calculation (released mid-2020)

Journal X published 25 papers in Issue Cover year 2017 and 20 papers in Issue Cover year 2018 (total 45). 40 of those papers were citable items (i.e. articles and reviews). The 45 papers received 50 citations from papers with an Issue Cover year of 2019.

An additional 5 papers were published in Early Access year 2018, but these would not have been indexed in Web of Science, and would not count in the Impact Factor denominator. These 5 Early Access papers received a further 3 citations in Issue Cover year 2019 (the citation rate is likely to be low, due to the short time between publication and the start of the citation window). These 3 citations cited the 2018 publication date so they would be included in the IF numerator.

2020 Impact Factor calculation (released mid-2021)

Journal X published 25 papers in Issue Cover year 2018 and 20 papers in Issue Cover year 2019 (total 45). 40 of those papers were citable items (i.e. articles and reviews). The 45 papers received 50 citations from papers with an Early Access year of 2020, and an additional 5 citations from papers with an Early Access year of 2019 but an Issue Cover year of 2020.

2021 Impact Factor calculation (released mid-2022)

Journal X published 20 papers in Issue Cover year 2019 and 25 papers in Early Access year 2020 (total 45). 40 of those papers were citable items (i.e. articles and reviews). The 45 papers received 50 citations with an Early Access year of 2021. Citations with an Early Access year of 2020 and an Issue Cover year of 2021 are not included.