In which fields are citations indicators of research quality?

Authors : Mike Thelwall, Kayvan Kousha, Emma Stuart, Meiko Makita, Mahshid Abdoli, Paul Wilson, Jonathan Levitt

Citation counts are widely used as indicators of research quality to support or replace human peer review and for lists of top cited papers, researchers, and institutions. Nevertheless, the relationship between citations and research quality is poorly evidenced. We report the first large-scale science-wide academic evaluation of the relationship between research quality and citations (field normalized citation counts), correlating them for 87,739 journal articles in 34 field-based UK Units of Assessment (UoA).

The two correlate positively in all academic fields, from very weak (0.1) to strong (0.5), reflecting broadly linear relationships in all fields. We give the first evidence that the correlations are positive even across the arts and humanities. The patterns are similar for the field classification schemes of Scopus and, although varying for some individual subjects and therefore more uncertain for these.

We also show for the first time that no field has a citation threshold beyond which all articles are excellent quality, so lists of top cited articles are not pure collections of excellence, and neither is any top citation percentile indicator. Thus, while appropriately field normalized citations associate positively with research quality in all fields, they never perfectly reflect it, even at high values.

URL : In which fields are citations indicators of research quality?


Do altmetric scores reflect article quality? Evidence from the UK Research Excellence Framework 2021

Authors : Mike Thelwall, Kayvan Kousha, Mahshid Abdoli, Emma Stuart, Meiko Makita, Paul Wilson, Jonathan Levitt

Altmetrics are web-based quantitative impact or attention indicators for academic articles that have been proposed to supplement citation counts. This article reports the first assessment of the extent to which mature altmetrics from and Mendeley associate with individual article quality scores.

It exploits expert norm-referenced peer review scores from the UK Research Excellence Framework 2021 for 67,030+ journal articles in all fields 2014–2017/2018, split into 34 broadly field-based Units of Assessment (UoAs). Altmetrics correlated more strongly with research quality than previously found, although less strongly than raw and field normalized Scopus citation counts.

Surprisingly, field normalizing citation counts can reduce their strength as a quality indicator for articles in a single field. For most UoAs, Mendeley reader counts are the best altmetric (e.g., three Spearman correlations with quality scores above 0.5), tweet counts are also a moderate strength indicator in eight UoAs (Spearman correlations with quality scores above 0.3), ahead of news (eight correlations above 0.3, but generally weaker), blogs (five correlations above 0.3), and Facebook (three correlations above 0.3) citations, at least in the United Kingdom.

In general, altmetrics are the strongest indicators of research quality in the health and physical sciences and weakest in the arts and humanities.

URL : Do altmetric scores reflect article quality? Evidence from the UK Research Excellence Framework 2021

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Researchers’ attitudes towards the h-index on Twitter 2007–2020: criticism and acceptance

Authors : Mike Thelwall, Kayvan Kousha

The h-index is an indicator of the scientific impact of an academic publishing career. Its hybrid publishing/citation nature and inherent bias against younger researchers, women, people in low resourced countries, and those not prioritizing publishing arguably give it little value for most formal and informal research evaluations.

Nevertheless, it is well-known by academics, used in some promotion decisions, and is prominent in bibliometric databases, such as Google Scholar. In the context of this apparent conflict, it is important to understand researchers’ attitudes towards the h-index.

This article used public tweets in English to analyse how scholars discuss the h-index in public: is it mentioned, are tweets about it positive or negative, and has interest decreased since its shortcomings were exposed?

The January 2021 Twitter Academic Research initiative was harnessed to download all English tweets mentioning the h-index from the 2006 start of Twitter until the end of 2020. The results showed a constantly increasing number of tweets.

Whilst the most popular tweets unapologetically used the h-index as an indicator of research performance, 28.5% of tweets were critical of its simplistic nature and others joked about it (8%). The results suggest that interest in the h-index is still increasing online despite scientists willing to evaluate the h-index in public tending to be critical.

Nevertheless, in limited situations it may be effective at succinctly conveying the message that a researcher has had a successful publishing career.


Can Google Scholar and Mendeley help to assess the scholarly impacts of dissertations?

Authors : Kayvan Kousha, Mike Thelwall

Dissertations can be the single most important scholarly outputs of junior researchers. Whilst sets of journal articles are often evaluated with the help of citation counts from the Web of Science or Scopus, these do not index dissertations and so their impact is hard to assess.

In response, this article introduces a new multistage method to extract Google Scholar citation counts for large collections of dissertations from repositories indexed by Google.

The method was used to extract Google Scholar citation counts for 77,884 American doctoral dissertations from 2013-2017 via ProQuest, with a precision of over 95%. Some ProQuest dissertations that were dual indexed with other repositories could not be retrieved with ProQuest-specific searches but could be found with Google Scholar searches of the other repositories.

The Google Scholar citation counts were then compared with Mendeley reader counts, a known source of scholarly-like impact data. A fifth of the dissertations had at least one citation recorded in Google Scholar and slightly fewer had at least one Mendeley reader.

Based on numerical comparisons, the Mendeley reader counts seem to be more useful for impact assessment purposes for dissertations that are less than two years old, whilst Google Scholar citations are more useful for older dissertations, especially in social sciences, arts and humanities.

Google Scholar citation counts may reflect a more scholarly type of impact than that of Mendeley reader counts because dissertations attract a substantial minority of their citations from other dissertations.

In summary, the new method now makes it possible for research funders, institutions and others to systematically evaluate the impact of dissertations, although additional Google Scholar queries for other online repositories are needed to ensure comprehensive coverage.