Citation impact of SA papers in WoS journal papers

2.7 The citation impact of South African-authored papers over the period 2005 – 2014

2.7.1 Citation impact of SA papers in WoS journal papers

The visibility and appreciation worldwide for South African science is partially captured by looking at the number of times research publications are referenced (‘cited’) in the publications of other researchers working in the same discipline or related fields. The number of citations is partially dependent on the research fields (some fields are ‘fast’, while others are ‘slow’) and need to be corrected for fair cross- field comparisons. This is what the ‘field-normalised citation impact’ score does. The other source of citation impact data, highly-cited publications, is generally seen as a mark of significant research impact on the scientific community.

Table 14. The share of South African science in global science – in total and by discipline* (1996-2015) Share of South African research publications in …

world publication

output top 10% cited

worldwide top 1% cited worldwide

All fields in total 0.6% 7.1% 0.6%

Medical and life sciences 0.6% 6.8% 0.7%

Natural sciences 0.5% 8.6% 0.7%

Engineering sciences 0.4% 7.8% 0.5%

Social and behavioural sciences 1.0% 4.0% 0.2%

Arts, humanities and law 1.1% 9.7% 1.2%

Language and communication 1.0% 3.5% 0.1%

Data source: CWTS TR WoS database (whole counting; research articles and letters)

* Selected broad disciplines originate from the NOWT classification system developed at CWTS, Leiden University.

Table 14 presents the share of South African (co-)authored research publications in world science.

Across all disciplines of science it amounts to 0.6% during the period 1996 – 2015. Some disciplines of SA science are better represented than others: we find a 1% share of SA publications in the social sciences and humanities. As for the collective citation impact of all those publications together, the field-

normalised citation impact for South Africa has gone up very gradually from 0.66, for the 4-year citation-

window 1996 – 1999, to an impact score of 1.03 for the period 2011 – 2014. Keeping in mind that a

score of 1.00 on this performance indicator represents world average citation impact (determined

98 mainly by the US and the leading nations of the world), our country has moved up from a performance level ‘below par’ to ‘international level’ in fewer than two decades.

Highly-cited publications are those that get noticed (and appreciated) among peers. These are the publications that make a difference in scientific progress and knowledge creation. South Africa

contributes significantly to the top 1% and top 10% most highly cited publications of the world. Across all disciplines of science, we find that 7.1% of all South African research publications are among the top 10% cited in their respective discipline. SA produces 9.7% of publications in arts, humanities and law.

The natural sciences in SA also produce fairly large numbers of highly-cited publications. Moving up to the top 1% cited in the world in their discipline, citations of South African articles account for 0.6% of that upper segment. SA publications in arts, humanities and law are again well-presented, along with natural sciences, but so are medical and life sciences from South Africa.

Many highly-cited publications represent a new discovery or another novelty that spark further research or open up new topics or areas of scientific enquiry. Some may lay the foundation for novel medical treatments or ‘game changing’ technologies. There is therefore a fair chance that the top 10% or top 1%

contains these ‘breakthrough discoveries’

⁷

. By their very nature these publications are quite rare. We applied CWTS-developed algorithms to identify those particular publications and determine the SA share in the breakthroughs (Figure 12).

7 The algorithms and a comparative analysis of their results are described in more detail in Winnink et al. (PlosOne 2016, forthcoming)

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Figure 12: Annual trend in the share of South Africa of the world publication output and within breakthrough research publications

Data source: CWTS TR WoS database (whole counting; research articles and letters)

The internationalisation of our science system and its rapid growth in publication output are also reflected in the increase of highly-cited SA publications and breakthroughs. Figure 13 displays some the annual trends. South Africa has almost doubled its share in world science since 1996, up from 0.45% to 0.80% in 2015. The trend in SA (co-produced) breakthrough publications is also upwards. Not only are the numbers of these publications increasing, their share in South African output has gone up

significantly from almost zero to 0.6% in 2012.

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Figure 13: Annual trend in the share of South Africa of highly-cited publications within its total publication output Data source: CWTS TR WoS database (whole counting; research articles and letters)

Figure 13 describes the related annual development with regards to the share of South Africa in the top

1% and top 10% most highly-cited research publications of the world. The upward trend lines mark an

increase in the share of these very highly-cited publications, which is of course one of the driving forces

of the overall increase of the research impact of South Africa. The output share in the top-10% segment

is still below 10%, fluctuating around 8%. By contrast, South African science has managed a significant

increase in top-1% cited publications over the years. That share is now well above 1% of the total

publication output of South Africa. In other words, our country is ‘over-represented’ in the upper

echelons of world science. Many of those extremely highly-cited publications are the product of

international scientific cooperation.

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