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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 3, May/June 2016
AFRICA
197
International collaboration and citation impact
Table 4 presents the 10-year trend in bibliometric outcomes
for publications in CVR with authorship involving SSA. The
table also compares research output and citation impact for
publications with single-country authorship (SCP) and those
with multi-country authorship (MCP). Overall, there was a
consistent increase in the total number of publications and total
number of citations each year from 2005 to 2014. The total
number of publications over the 10-year period was similar for
SCP and MCP, as shown by the publication ratio, with a slight
increase from 0.7 in 2005 to 1.2 in 2014. Total citations rose from
20 in 2005 to 2 973 in 2014.
There were substantial differences between the SCP and
MCP in the citation frequency and citation rate (CR, number of
citations per publication) throughout the period of analysis. On
average, the annual citation frequency for MCP was 3.4 times
higher than the annual citation frequency for SCP. Over 10 years,
the total number of citations for the MCP was 10 116, compared
to 3 117 for the SCP. Comparisons of citation rates for the two
categories using the annual CR ratio showed that the CR for
MCP was on average 3.6 times higher than that for SCP.
Discussion
This study provides a 10-year picture of the range, volume
and scientific impact of international collaboration in
cardiovascular research in sub-Saharan Africa. The absence
of published literature on this issue suggests that this is the
first study that evaluates the comparative output of SSA
countries in cardiovascular research and examines the patterns
of co-authorship involving country-level affiliations within and
outside SSA.
A study in 2005 on estimates of the global production in
CVR showed that the scientific productivity of Africa (which
included SSA and countries in North Africa) over the period
1995 to 2002 was the lowest of all the world regions, accounting
for 0.3% of the global output in the field.
18
Over the eight-year
period, Africa produced 212 articles in the 38 journals included
in the study, with a fairly constant average annual output of 27
articles per year.
In the present study, the annual output for SSA increased
constantly from 88 in 2005 to 225 in 2014. The higher annual
output in this study may be due to the difference in search
methodology, in which published articles were not restrictively
drawn from the 38 journals in the ‘Cardiac and Cardiovascular
Systems’ category of ‘Journal Citation Report’ as was done in
the study mentioned above.
18
In general, there appears to be a
gradual increase in research output in this field in SSA, although
the contribution of the region to the global output remains very
low.
Some of the reasons for the lower research productivity in
SSA were mentioned above – lack of resources for research,
the fewer number of research institutions, weak government
support, and the dearth of skilled researchers in many fields of
Table 4. Comparison of annual count and citations for single-country (SSA) authored and multi-country (international) authored cardiovascular
research publications
All publications
Single-country publications (SCP)
Multi-country publications* (MCP)
Comparisons (MCP/SCP)
Year
Total
publications
Total
citations Publications Citations
Citation rate
(CR) Publications Citations
Citation rate
(CR)
Publication
ratio
Citation
ratio
CR ratio
2005
88
20
51
4
0.1
37
16
0.4
0.7
4.0
5.5
2006
101
247
55
52
0.9
46
195
4.2
0.8
3.8
4.5
2007
108
547
58
122
2.1
50
425
8.5
0.9
3.5
4.0
2008
149
702
66
150
2.3
83
552
6.7
1.3
3.7
2.9
2009
156
1008
88
231
2.6
68
777
11.4
0.8
3.4
4.4
2010
163
1247
84
325
3.9
79
922
11.7
0.9
2.8
3.0
2011
164
1762
82
425
5.2
82
1337
16.3
1.0
3.1
3.1
2012
197
2104
96
498
5.2
101
1606
15.9
1.1
3.2
3.1
2013
218
2623
105
581
5.5
113
2042
18.1
1.1
3.5
3.3
2014
225
2973
101
729
7.2
124
2244
18.1
1.2
3.1
2.5
Total
1569
13233
786
3117
4.0
783
10116
12.9
1.0
3.2
3.3
Average
157
1,323
79
312
3.5
78
1012
11.1
1.0
3.4
3.6
*This refers to all multi-country publications that included at least one SSA country among the author affiliations.
Table 3. Number of instances of cardiovascular research collaboration between the top 10 countries in sub-Saharan Africa, 2005–2014
South Africa
(%)
Nigeria
(%)
Cameroon
(%)
Uganda
(%)
Zimbabwe
(%)
Mozambique
(%)
Kenya
(%)
Ghana
(%)
Tanzania
(%)
Senegal
(%)
All SSA
(%)
South Africa
15 (27)
5 (9)
2 (4)
8 (15)
8 (15)
3 (5)
6 (11)
1 (2)
1 (2)
55
Nigeria
15 (58)
2 (8)
1 (4)
1 (4)
–
–
1 (4)
1 (4)
2 (8)
26
Cameroon
5 (16)
2 (6)
1 (3)
1 (3)
–
–
3 (9)
1 (3)
4 (13)
32
Uganda
2 (17)
1 (8)
1 (8)
1 (8)
–
1 (8)
–
1 (8)
–
12
Zimbabwe
8 (50)
1 (6)
1 (6)
1 (6)
–
–
–
1 (6)
–
16
Mozambique
8 (89)
–
–
–
–
–
–
–
–
9
Kenya
3 (30)
–
–
1 (10)
–
–
2 (20)
–
–
10
Ghana
6 (38)
1 (6)
3 (19)
–
–
–
2 (13)
–
–
16
Tanzania
1 (13)
1 (13)
1 (13)
1 (13)
1 (13)
–
–
–
–
8
Senegal
1 (7)
2 (14)
4 (29)
–
–
–
–
–
–
14
Numbers in parentheses are row percentages using the total number of instances of collaboration with all countries in SSA as denominator.