RESEARCH ARTICLE - Am MIT spezialisierte KI-Forschung

RESEARCH ARTICLE

Comprehensive mapping of local and diaspora
Wissenschaftler: A database and analysis of
63,951 Greek scientists

John P. McCarthy. A. Ioannidis1

, Chara Koutsioumpa2

, Angeliki Vakka3

, Georgios Agoranos4

Chrysanthi Mantsiou5
Despina G. Contopoulos-Ioannidis8

, Maria Kyriaki Drekolia6

, Nikos Avramidis7

, Konstantinos Drosatos9,10

, and Jeroen Baas11

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1Stanford Prevention Research Center, Department of Medicine, and Department of Epidemiology and Population Health,
Stanford University School of Medicine and Meta-Research Innovation Center at Stanford (METRICS), Stanford, Kalifornien, USA
2Abteilung für Neurobiologie, Harvard Medical School, Boston, USA
3School of Medicine, University of Patras, Greece
4Hellenic Center of Mental Health and Research (EKEPSYE), Athen, Greece
5Clinical Research and Evidence-Based Medicine Unit, Second Medical Department,
Aristotle University of Thessaloniki, Thessaloniki, Greece
6Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Frankfurt am Main, Deutschland
7Roslin Institute, University of Edinburgh
8Abteilung für Pädiatrie, Stanford University School of Medicine, Stanford, Kalifornien, USA
9Department of Pharmacology, Center for Translational Medicine, Lewis Katz School of Medicine,
Temple University, Philadelphia, PA, USA
10ARISTEiA-Institute for the Advancement of Research & Education in Arts, Wissenschaften & Technologie, McLean, VA, USA
11Sonst, Amsterdam, Niederlande

Schlüsselwörter: brain drain, diaspora, Greece, science mapping, scientific workforce

ABSTRAKT

Research policy and planning for a given country may benefit from reliable data on both its
scientific workforce as well as the diaspora of scientists for countries with a substantial brain
drain. Here we use a systematic approach using Scopus to generate a comprehensive country-
level database of all scientists in Greece. Darüber hinaus, we expand that database to include also
Greek diaspora scientists. The database that we have compiled includes 63,951 scientists who
have published at least five papers indexed in Scopus. Of those, 35,116 have an affiliation in
Greece. We validate the sensitivity and specificity of the database against different control sets of
Wissenschaftler. We also analyze the scientific disciplines of these scientists according to the Science
Metrix classification (174 subfield disciplines) and provide detailed data on each of the 63,951
scientists using multiple citation indicators and a composite thereof. These analyses demonstrate
differential concentrations in specific subfields for the local versus the diaspora cohorts, als
well as an advantage of the diaspora cohort in terms of citation indicators, especially among
top-impact researchers. The approach that we have taken can also be applied to map the
scientific workforce of other countries and nations for evaluation, planning, and policy purposes.

EINFÜHRUNG

The construction of scientist databases can be a useful tool for evaluation, planning, and policy-
making related to science. Efforts to compile national databases of scientists with performance
metrics, in particular citation indices, are sometimes undertaken by research assessment author-
ities (Moed, 2008; Rijke, Wouters et al., 2016). Often these efforts may not be sufficiently

Keine offenen Zugänge

Tagebuch

Zitat: Ioannidis, J. P. A.,
Koutsioumpa, C., Vakka, A., Agoranos,
G., Mantsiou, C., Drekolia, M. K.,
Avramidis, N., Contopoulos-Ioannidis,
D. G., Drosatos, K., & Baas, J. (2021).
Comprehensive mapping of local and
diaspora scientists: A database and
analysis of 63,951 Greek scientists.
Quantitative Science Studies, 2(2),
733–752. https://doi.org/10.1162/qss_a
_00136

DOI:
https://doi.org/10.1162/qss_a_00136

Peer Review:
https://publons.com/publon/10.1162
/qss_a_00136

Erhalten: 21 Januar 2021
Akzeptiert: 24 Marsch 2021

Korrespondierender Autor:
John P. McCarthy. A. Ioannidis
jioannid@stanford.edu

Handling-Editor:
Ludo Waltman

Urheberrechte ©: © 2021 John P. McCarthy. A. Ioannidis,
Chara Koutsioumpa, Angeliki Vakka,
Georgios Agoranos, Chrysanthi
Mantsiou, Maria Kyriaki Drekolia,
Nikos Avramidis, Despina G.
Contopoulos-Ioannidis, Konstantinos
Drosatos, and Jeroen Baas. Published
under a Creative Commons
Namensnennung 4.0 International
(CC BY 4.0) Lizenz.

Die MIT-Presse

Comprehensive mapping of local and diaspora scientists

inclusive. Zum Beispiel, they may depend on nonsystematic efforts where scientists voluntarily
contribute information themselves to be included. Darüber hinaus, citation metrics are difficult to
standardize, especially when they are not calculated according to the same processes for all
Wissenschaftler, and when differences between scientific fields are insufficiently accounted for.
Wichtig, for many countries, brain drain is a major challenge for their scientific workforce
(Doria Arrieta, Pammolli, & Petersen, 2017; Ioannidis, 2004; Veugelers, 2017). In these coun-
versucht, planning and policy decisions would greatly benefit from mapping not only the disciplines
and impact of scientists who still work in the country but also of those who have emigrated else-
Wo. First-generation emigrating scientists and often even second and higher generation em-
igrants may often still be interested in engaging with the scientific workforce of their country of
origin, thus contributing valuable expertise. Countries with strong diaspora may benefit from the
skills of diaspora scientists. Scientific diaspora can be useful for both the mobile scientists
(Halevi, Moed, & Bar-Ilan, 2016; Petersen, 2018; Robinson-Garcia, Sugimoto, et al., 2019)
and the countries involved at both ends, as it can constitute a modern tool of scientific diplomacy
and cooperation between the two countries (Stark, Helmenstein & Prskawetz, 1997; Wagner &
Jonkers, 2017).

Here we demonstrate how a large-scale standardized approach can be used to create an
inclusive, comprehensive database of scientists in a specific nation. Darüber hinaus, we show how
one can expand that database to include also scientists who have migrated to other countries.
We focus our efforts on Greece and its national workforce and scientific diaspora. Greece is a
country that has sustained a very strong current of brain drain over the years (Ifanti, Argyriou
et al., 2014; Moris, Karachaliou, & In den Konten, 2017; Theodoropoulos, Kyridis et al., 2014;
Trachana, 2013). Darüber hinaus, the country has been hit by a major economic crisis that has se-
verely limited funding for research and development. Despite some improvements in recent
Jahre, funding remains highly suboptimal. Außerdem, scientists of Greek origin include
many extremely influential scientists worldwide and past analyses suggest that there are many
high-impact Greek scientists, both in Greece and abroad, who are leaders in their fields (Yurte,
2017). Darüber hinaus, such previous work has suggested that the number of Greek scientists with
substantial impact is much higher proportionately than the share of Greeks in the global pop-
ulation (10 million in Greece and perhaps another 3 million in the diaspora) (Yurte, 2017).
Mapping Greek scientists in Greece and worldwide would be a valuable resource. The avail-
ability of comprehensive science publications databases such as Scopus and the fact that
many Greek first names and a large majority of Greek last names tend to be highly specific
for Greek descent allow the creation of a database of scientists of Greek origin. In diesem Papier,
we describe how we have constructed such a database and how we have examined its sen-
sitivity and specificity in validation samples. We also present descriptive data for the entire
database and for comparative evaluations of Greek origin scientists who have an affiliation
in Greece and for those who have an affiliation in other countries. Our work may offer a tem-
plate for similar scientist-mapping efforts on other countries.

2. METHODEN

2.1. Eligibility Criteria

We aimed to capture all scientists of Greek origin who have at least five published papers (articles,
Bewertungen, and conference proceedings). Eligible scientists were both those born in Greece and
those born elsewhere (second or higher generation), but whose family had a Greek origin.
Scientists were eligible regardless of whether they had their current main affiliation in Greece
oder anderswo. We excluded scientists who had fewer than two papers published after 1950.

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The overall strategy aimed at finding typical Greek names first and then retrieving all author
profiles with these names. To capture eligible scientists with an affiliation in Greece, we queried
Scopus (Baas, Schotten et al., 2020) as of January 15, 2020 and identified all the last names that
had at least one author ID (with any number of papers assigned) that included an affiliation in
Greece. We found 70,967 names where at least one author ID has an affiliation address in
Greece. One researcher manually screened all of these names to identify those that seemed
to be of Greek origin, allowing for inclusion of those who might be probable, to avoid losing
potentially eligible names. A second researcher then examined the manual extraction and made
amendments. Eventually, 57,732 last names were retained.

We also screened manually the files of the top 100,000 most cited scientists based on a
composite indicator that had been published previously (Ioannidis, Baas et al., 2019). Wir verwendeten
three different files of the top-cited scientists, each of which captured the top 100,000 inkl-
ing self-citations as well as the top 100,000 excluding self-citations based on career-long data
in Scopus until the end of 2017 (https://dx.doi.org/10.17632/btchxktzyw.1#file-ad4249ac-f76f
-4653-9e42-2dfebe5d9b01); based on citations received during a single calendar year (2017)
(https://dx.doi.org/10.17632/btchxktzyw.1#file-b9b8c85e-6914-4b1d-815e-55daefb64f5e);
and based on career-long data until the end of 2018 (https://dx.doi.org/10.17632/btchxktzyw
.1#file-bade950e-3343-43e7-896b-fb2069ba3481). These three files manually yielded 1,044,
990, Und 1,013 eligible authors of Greek origin, with large overlap between the three lists.

Zusätzlich, two online sources of common Greek first names (forebears.io and www
.studentsoftheworld.info/penpals/stats.php?Pays=GRE) were screened manually starting from
the most common ones until 86 first names were selected that were thought to be relatively
specific for Greek origin people. Zum Beispiel, George is a common name in Greece, aber es ist
not Greek specific (d.h., the vast majority of people with first name George are not of Greek
origin). Umgekehrt, Georgios is highly Greek specific.

At the next step, we retrieved from Scopus all author ID files with at least five papers (articles,
Bewertungen, or conference papers) where scientists had either a seemingly Greek-specific last name
(any of the 57,332 last names mentioned above, or any of the last names of highly cited Greek sci-
entists according to any of the three previously published lists) or a seemingly Greek-specific first
name (any of the 86 mentioned above). Eventually, 124,656 author ID files were retrieved.

Diese 124,656 files were manually screened, perusing the information for each scientist,
including the first name, last name, country of listed affiliation, and institution of listed affiliation
that could help identify if the scientist was of Greek origin or not. The availability of all scientists
who shared one of the seemingly Greek-specific names along with country information allowed
us to identify whether any of these names were in fact not Greek-specific. Some last names occur
identically both in Greeks and in some other nationality (z.B., Adam or Spinelli). In these cases,
information on first name could help classify that individual if the first name was characteristi-
cally Greek. If the first name did not help to differentiate in this regard, the country information
was used to arbitrate. The site https://forebears.io/ was consulted also in ambiguous cases,
because it shows the relative frequency of surnames and names across different countries. Wenn ein
scientist in a given country had a surname that appeared more frequently in Greece than in other
Länder, she or he was considered of Greek origin.

Von 124,656 author files, it was concluded that 62,837 were very likely Greek. We listed
alphabetically by last names the 62,837 authors and recorded additional first names that
seemed to be Greek specific. By screening 2,000 names at a time, it was found that relatively
few new Greek-specific names were added after screening 8,000 authors and the incremental
addition of eligible Greek origin authors would be limited by adding more first names. Das

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Comprehensive mapping of local and diaspora scientists

process yielded 370 seemingly Greek-specific first names and we then searched Scopus for all
additional author IDs with these first names that had not been already captured in the 62,837.
These additional authors were then manually screened, Und 1,012 were deemed (based on
their name and country information) to be eligible. The resulting database, umfassend
63,849 author IDs, was subjected to validation checks as described below. Additions and de-
letions emerging during these validation checks and a final contribution by the authors of the
present study of Greek scientists they knew of but who had not been captured increased the
final count by 102 to a final count of 63,951 author IDs.

The process is summarized in Figure 1.

2.2. Validierung: Sensitivity for Capturing Scientists of Greek Origin Who Are in Greece

To evaluate the sensitivity of the compiled database in capturing scientists who work in
Greece, we searched whether it had included scientists working at a university in Greece,
the University of Thessaly. Scientists working in different universities and research institutions
in Greece are not likely to have systematically different names, so one university is likely to
provide a reasonably representative sample. We searched Google Scholar as the reference

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Figur 1. Flow diagram for identification of Greek scientists.

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database, as scientists need to enter their names and affiliations by themselves in creating a
profile in Google Scholar. Der 130 most cited scientists with profiles and University of
Thessaly affiliation in Google Scholar were screened and it was found that all of them (130/130)
had been included in our compiled database. daher, the sensitivity was 100%, with binomial
95% confidence interval of 97.2% Zu 100%.

2.3. Validierung: Sensitivity for Capturing Scientists of Greek Origin Who Are not in Greece

To evaluate the sensitivity of the compiled database in capturing scientists of Greek origin who
do not work in Greece, we used two approaches.

Erste, we used a sample of scientists who had entered their names in a LinkedIn database of
Greek biomedical scientists created by one of us (K. D.) for the World Hellenic Biomedical
Association. We only considered names that had been entered by the scientists themselves,
proving that they identified themselves as Greek; and we further limited the search to scientists
who gave an address outside of Greece and who had a work title suggesting that they are
faculty or other people in senior positions, as opposed to students. Von 42 such individuals,
34 were found to have at least five papers in Scopus. Of those 34, 26 were captured in the
compiled database, for a sensitivity of 76.5% (95% confidence interval, 58.8% Zu 89.3%).

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Zweite, we used the names of people listed in the Wikipedia entry on Greek Diaspora. Diese
names are not necessarily of scientists; therefore we examined whether each of the names would
have been captured either through one of the Greek-specific last names or through one of the first
Greek-specific names that we had put together to compile our database of Greek scientists. Für
artists and other people who had acquired an artistic/stage name, we used their original name, als
changing to artistic/stage names would not apply for scientists. We excluded from the screening
people born before 1900, as Greek names in the remote past may have been different.
Eventually, 28 first-generation and 88 zweite- or later-generation Greeks were eligible for
screening. Of these 14/28 Und 35/88 would have been captured by our last or first name
searches, corresponding to sensitivities of 50% (95% confidence interval, 30.6% Zu 69.4%)
Und 39.8% (95% confidence interval, 29.4% Zu 50.8%), jeweils.

The sensitivity estimates should be interpreted cautiously given the relatively small numbers

and they leave some uncertainty about the total number of diaspora scientists.

2.4. Validierung: Specificity for Capturing Scientists of Greek Origin

To evaluate whether the compiled database might have captured any scientists who were not
actually Greek, we randomly selected 100 of the 63,849 author IDs. For each of them, we tried to
find whether we could find their name written in Greek in the web. Of the 100, their Scopus
affiliation was in Greece for 62, in Cyprus for four, and in other countries for 32; for two authors
we had no listed affiliation in Scopus. We could find their name written in Greek for all 100
authors. daher, the specificity was 100% (95% confidence interval 96.4% Zu 100%).

2.5. Evaluation of Split Author Files

Some scientists in Scopus may have their published work split in two or more author ID files,
and Scopus encourages authors to communicate directly with them to merge such split files. To
assess how common this pattern might be in the compiled database of Greek authors, after list-
ing the names alphabetically, every 600th name was selected and assessed whether more than
one author ID files may exist for that person in the database. Von 106 screened names, neun
(8.5%, 95% CI, 4.0 Zu 15.5%) had their work split into two files (n = 8) or three files (n = 1).

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2.6. Data Included for Each Scientist in the Database

From each author ID file included in the database, the following information is included based
on data directly imported from Scopus on October 1, 2020 (Wann 7,983,030 author ID files
with at least five papers (articles, Bewertungen, or conference papers) were available in Scopus) Und
calculations that are the same as those performed for a recently published list of top-cited
Wissenschaftler (Ioannidis, Boyack, & Baas, 2020): affiliation and country; publication year of earlier
and latest Scopus-indexed publication; number of publications; number of publications in
1960–2020; six citation indicators (total citations, h-index, hm-index, citations to single-
authored publications, citations to first- or single-authored publications, citations to first-,
single-, or last-authored publications) and their composite (all indicators being presented both
with and without self-citations); proportion of self-citations; ratio of citations to citing papers;
ranking according to the composite indicator among all scientists worldwide with at least five
Papiere; most common field of publications according to the 22-field Science Metrix classifi-
cation; two most common subfields of publications according to the 174-subfield Science
Metrix classification; and ranking according to the composite indicator among all the scientists
in the same main (most common) Science Metrix subfield. For details on the Science Metrix
classification see Archambault, Beauchesne, and Caruso (2011) and Zhang, Zhao, and LeCun
(2015). For authors where Scopus listed an affiliation but not a country, we tried to identify the
country whenever it would be unambiguous based on the provided affiliation.

3. ERGEBNISSE

3.1. Main Descriptive Characteristics

Of the 63,951 author ID files included in the final database, country of affiliation was available
für 63,174, Und 35,116 (55.6%) of them had their affiliation in Greece. Large shares of this cohort

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Figur 2. Worldwide distribution of scientists.

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of scientists were also located in the United States (n = 9,339, 14.8%), Großbritannien (n =
6,165, 9.8%), Deutschland (n = 2,083, 3.3%), Cyprus (n = 1,688, 2.7%), Australia (n = 1,155,
1.8%), Frankreich (n = 1,141, 1.8%), Kanada (n = 1,110, 1.8%), and Switzerland (n = 994,
1.6%), but the diaspora was worldwide (Figur 2).

A total of 12,299 (19.2%) scientists had published their first Scopus-indexed paper after
2010 Und 38,248 (59.8%) had been recently active, publishing their last paper in 2018 oder später.
The median number of published papers was 13 (interquartile range 8 Zu 31) and the median
number of citations was 153 (interquartile range 52 Zu 478).

As shown in Table 1, scientists with affiliation in Greece had a similar number of papers to
scientists with affiliation outside of Greece, but they had substantially fewer citations and
fewer papers that cited their work, and were placed on average in lower ranks compared with
scientists with affiliation outside of Greece. The results were qualitatively similar regardless of
whether self-citations were counted or excluded (Tisch 1). Scientists with affiliation outside of
Greece tended to have younger publication ages (median for year of first publication 2004
versus 2002).

A total of 33,956 scientists with affiliation in Greece and 26,150 scientists with affiliation in
other countries could be assigned to a main scientific subfield. Among scientists who were in
the top 0.1% of their subfield, the vast majority (86%) of them had an affiliation outside of
Greece rather than in Greece (96 versus 15). For the top 0.5%, the respective numbers were
348 versus 89, for the top 1% the respective numbers were 648 versus 250, and for the top 5%
the respective numbers were 2,438 versus 1,724, always with a strong preponderance of

Tisch 1.

Characteristics of scientists according to their country of current affiliation

Characteristic, median (IQR)
Number of papers

Year of first paper

Year of most recent paper

Ranking across all science,

thousands (excluding self-citations)

Citations (excluding self-citations)

Citing papers (excluding self-citations)

Citations to citing papers ratio (excluding self-citations)

Percentage of self-citations

Affiliation in Greece
n = 35,116

13 (7–30)

2002 (1993–2008)

2019 (2013–2020)

3,505 (1,691–5,463)

139 (50–408)

131 (48–375)

1.04 (1.00–1.11)

14 (7–25)

Affiliation in other
country n = 28,058

14 (8–32)

2004 (1994–2010)

2019 (2014–2020)

2,812 (1,265–4,730)

184 (59–609)

169 (55–541)

1.07 (1.02–1.16)

15 (8–25)

Ranking across all science, thousands (with self-citations)

3,508 (1,681–5,458)

2,801 (1,259–4,697)

Citations (with self-citations)

Ranking in main subfield (with self-citations)

Ranking in main subfield (without self-citations)

Percentile in main subfield (with self-citations)

Percentile in main subfield (without self-citations)

169 (63–486)

28,711 (11,338–61,183)

28,693 (11,312–61,180)

46 (22–71)

226 (76–730)

21,378 (7,500–48,629)

21,324 (7,535–48,751)

37 (16–61)

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Tisch 2. Number of scientists in each scientific subfield

Greece
20

Other
32

Unknown
0

Total
52

Country

Scientific subfield
Accounting

Acoustics

Aerospace & Aeronautics

Agricultural Economics & Policy

Agronomy & Landwirtschaft

Allergy

Analytical Chemistry

Anatomy & Morphology

Anesthesiology

Anthropology

Applied Ethics

Applied Mathematics

Applied Physics

Archaeology

Architecture

Art Practice, Geschichte & Theory

Arthritis & Rheumatology

Artificial Intelligence & Image Processing

Astronomy & Astrophysics

Automobile Design & Maschinenbau

Behavioral Science & Comparative Psychology

Biochemistry & Molecular Biology

Bioinformatics

Biomedizintechnik

Biophysics

Biotechnology

Building & Construction

Business & Management

Cardiovascular System & Hematology

Chemical Engineering

Chemical Physics

Quantitative Science Studies

D
Ö
w
N
Ö
A
D
e
D

F
R
Ö
M
H

T
T

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/
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ich
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.

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3
3
1
9
3
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6
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7
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3

112

211

368

130

160

632

107

194

1,685

166

286

262

181

168

200

1,671

220

200

154

159

194

100

586

126

1,293

246

474

105

248

128

148

203

768

236

234

266

219

265

142

564

211

261

1,218

168

320

2,985

413

760

177

511

135

309

316

403

2,449

456

435

740

Comprehensive mapping of local and diaspora scientists

Tisch 2.

(Fortsetzung )

Scientific subfield
Civil Engineering

Classics

Clinical Psychology

Communication & Media Studies

Complementary & Alternative Medicine

Computation Theory & Mathematik

Computer Hardware & Architecture

Criminology

Cultural Studies

Dairy & Animal Science

Demographie

Dentistry

Dermatology & Venereal Diseases

Design Practice & Management

Development Studies

Developmental & Child Psychology

Developmental Biology

Distributed Computing

Drama & Theater

Ecology

Econometrics

Economic Theory

Economics

Education

Electrical & Electronic Engineering

Emergency & Critical Care Medicine

Endocrinology & Metabolism

Energy

Entomology

Environmental & Occupational Health

Environmental Engineering

Quantitative Science Studies

Greece
249

Other
251

Unknown
2

Total
502

Country

123

173

214

421

209

172

119

310

456

293

183

577

869

195

246

119

164

287

150

712

286

329

267

342

591

119

243

337

268

713

360

129

884

158

192

596

785

560

276

928

1,467

243

366

741

D
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3
3
1
9
3
0
7
2
5
Q
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0
0
1
3
6
P
D

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T

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N
0
7
S
e
P
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M
B
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R
2
0
2
3

Comprehensive mapping of local and diaspora scientists

Tisch 2.

(Fortsetzung )

Scientific subfield
Environmental Sciences

Epidemiology

Evolutionary Biology

Experimental Psychology

Family Studies

Finance

Fisheries

Fluids & Plasmas

Folklore

Food Science

Forestry

Gastroenterology & Hepatology

Gender Studies

Allgemein & Internal Medicine

General Chemistry

General Clinical Medicine

General Mathematics

General Physics

General Psychology & Cognitive Sciences

Genetik & Heredity

Geochemistry & Geophysics

Geography

Geological & Geomatics Engineering

Geology

Geriatrics

Gerontology

Health Policy & Dienstleistungen

Geschichte

History of Science, Technologie & Medicine

History of Social Sciences

Horticulture

Quantitative Science Studies

Greece
534

Other
163

Unknown
0

Total
697

Country

146

159

377

661

375

102

237

131

270

272

138

159

195

132

252

231

162

151

174

167

187

121

178

254

193

354

513

124

915

611

140

399

282

270

445

460

124

742

D
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w
N
Ö
A
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D

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H

T
T

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T
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C
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2
2
7
3
3
1
9
3
0
7
2
5
Q
S
S
_
A
_
0
0
1
3
6
P
D

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G
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S
T

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N
0
7
S
e
P
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M
B
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R
2
0
2
3

Comprehensive mapping of local and diaspora scientists

Tisch 2.

(Fortsetzung )

Scientific subfield
Human Factors

Immunology

Industrial Engineering & Automation

Industrial Relations

Information & Library Sciences

Information Systems

Inorganic & Nuclear Chemistry

International Relations

Languages & Linguistik

Law

Legal & Forensic Medicine

Literary Studies

Logistics & Transportation

Marine Biology & Hydrobiology

Marketing

Materials

Mathematical Physics

Mechanical Engineering & Transports

Medical Informatics

Medicinal & Biomolecular Chemistry

Meteorology & Atmospheric Sciences

Microbiology

Microscopy

Mining & Metallurgy

Musik

Mycology & Parasitology

Nanoscience & Nanotechnology

Networking & Telecommunications

Neurologie & Neurochirurgie

Nuklear & Particle Physics

Nuclear Medicine & Medical Imaging

Quantitative Science Studies

Greece
28

Other
77

Unknown
0

Country

706

332

143

250

173

247

390

253

184

236

306

896

1,100

742

509

575

487

390

204

128

155

280

218

149

223

367

134

953

962

623

377

Total
105

1,194

722

351

379

114

329

331

131

671

472

262

385

529

1,267

209

2,063

1,707

1,132

953

743

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N
Ö
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1
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3
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1
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6
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N
0
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2
3

Comprehensive mapping of local and diaspora scientists

Tisch 2.

(Fortsetzung )

Scientific subfield
Numerical & Computational Mathematics

Nursing

Nutrition & Dietetics

Obstetrics & Reproductive Medicine

Oceanography

Oncology & Carcinogenesis

Operations Research

Ophthalmology & Optometry

Optics

Optoelectronics & Photonics

Organic Chemistry

Ornithology

Orthopedics

Otorhinolaryngology

Paleontology

Pathology

Pädiatrie

Pharmacology & Pharmacy

Philosophy

Physical Chemistry

Physiology

Plant Biology & Botany

Political Science & Public Administration

Polymers

Psychiatrie

Psychoanalysis

Public Health

Rehabilitation

Religions & Theology

Respiratory System

Science Studies

Quantitative Science Studies

Greece
92

147

230

636

102

1,718

138

301

258

232

461

206

123

226

396

172

498

282

277

534

Country

Other
51

Unknown
0

126

303

868

118

308

155

319

212

348

128

113

208

161

107

222

265

139

255

Total
143

237

356

940

145

2,589

256

609

229

578

444

810

334

194

341

604

262

659

162

505

544

226

104

790

744

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Ö
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7
3
3
1
9
3
0
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0
0
1
3
6
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2
3

Comprehensive mapping of local and diaspora scientists

Greece
30

Other
74

Unknown
1

Country

Tisch 2.

(Fortsetzung )

Scientific subfield
Social Psychology

Social Sciences Methods

Social Work

Sociology

Software Engineering

Speech-Language Pathology & Audiology

Sport Sciences

Sport, Leisure & Tourism

Statistics & Probability

Strategic, Defence & Security Studies

Substance Abuse

Surgery

Toxicology

Tropical Medicine

Urban & Regional Planning

Urology & Nephrology

Veterinary Sciences

Virology

Zoology

331

144

160

760

114

549

164

126

104

132

493

223

154

1,269

196

117

773

237

240

Total
105

192

103

435

119

276

259

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3
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1
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6
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3

scientists who were not in Greece (79%, 72%, Und 59%, jeweils, for these three thresh-
olds). Below the top 5%, there was more equilibrium between scientists with affiliation outside
of Greece versus in Greece, with the respective numbers being 7,842 versus 7,807 für die
top 20%.

3.2. Scientific Fields

As shown in Table 2, Greek scientists had different representation across the 174 main scien-
tific subfields of the Science Metrix classification. A number of fields of clinical medicine, bi-
ology, and agriculture/fisheries/forestry are more heavily represented for scientists who are in
Greece, while the diaspora is more prominently represented in several social and economic
sciences and some cutting-edge biomedical fields. Für 25 subfields, scientists in Greece ex-
ceeded by more than 2:1 scientists with affiliation outside of Greece (Anatomy & Morphology,
Environmental Engineering, Respiratory System, Obstetrics & Reproductive Medicine,
Cardiovascular System & Hematology, Veterinary Sciences, Medical Informatics,
Oceanography, Microbiology, Urology & Nephrology, Gastroenterology & Hepatology,
General Clinical Medicine, Food Science, Marine Biology & Hydrobiology, Plant Biology &

Quantitative Science Studies

745

Q
u
A
N

T
ich
T

ich

T
ich
v
e
S
C
e
N
C
e
S
u
D
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S

ich

Tisch 3.

Scientists who are among the top 15 of their scientific subfield according to a composite citation indicator, excluding self-citations

Country
aus

Subfield

Building & Construction

Rank*
1

n in subfield**
27299

First degree

U Patras

Name of scientist
Santamouris, Mattheos

Affiliation

University of New South Wales

(UNSW) Australia

Peppas, Nicholas A.

The University of Texas at Austin

Terzopoulos, Demetri

Universität von Kalifornien, Los Angeles

Nicolaides, Kypros H.

King’s College Hospital

usa

gbr

Pharmacology & Pharmacy

Software Engineering

Obstetrics & Reproductive

Medicine

Papadimitriou, Christos H. Columbia University in the City of

usa

Computation Theory &

New York

Mathematik

Ioannidis, John P. McCarthy. A.

Stanford University School of Medicine

Stamatakis, Alexandros

Karlsruhe Institute of Technology

Joannopoulos, John

Massachusetts Institute of Technology

Alivisatos, A. Paul

Universität von Kalifornien, Berkeley

Ntziachristos, Vasilis

Helmholtz Center Munich

German Research Center for
Environmental Health

Guibas, Leonidas J.

Universität in Stanford

Buhalis, Dimitrios

Bournemouth University

Giannelis, Emmanuel

Cornell University

Kanatzidis, Mercouri G.

Nordwestliche Universität

Simopoulos, Artemis P.

Center for Nutrition, Genetik

& Health

Bertsekas, Dimitri

Arizona State University

Pavlou, Paul

C. T. Bauer College of Business

Stephanopoulos, Gregory Massachusetts Institute of Technology

Nicolaou, K. C.

Rice University

Diamantopoulos,
Adamantios

Universitat Wien

Gazetas, G.

National Technical University

of Athens

usa

deu

usa

deu

usa

gbr

usa

aut

grc

Allgemein & Internal Medicine

Bioinformatics

Optoelectronics & Photonics

Nanoscience &

Nanotechnology

Nuclear Medicine &
Medical Imaging

Software Engineering

Sport, Leisure & Tourism

Polymers

Materials

Nutrition & Dietetics

Operations Research

Information Systems

Biotechnology

Organic Chemistry

Marketing

Strategic, Defence &
Security Studies

7
4
6

C
Ö
M
P
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e
N
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v
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A
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P
ich
N
G

Ö
F

l
Ö
C
A
l

A
N
D

D
ich
A
S
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C
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T
ich
S
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95625

21515

66792

NTUA

McGill

King’s College

16762

NTUA

107698

U Athens

18635

TU Munich

102335

UC Berkeley

75646

U Chicago

84992

Aristotle U

21515

CalTech

6295

U Aegean

81179

U Athens

180221

Aristotle U

35890

23674

16831

50679

Barnard

College

NTUA

Rice U

NTUA

112004

U London

10516

Heriot-Watt U

17396

NTUA

Q
u
A
N

T
ich
T

ich

T
ich
v
e
S
C
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N
C
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S
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D
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S

ich

Antonarakis, Stylianos E.

Université de Genève Faculté de

che

Genetik & Heredity

Pratsinis, Sotiris E.

ETH Zürich

Médecine

Chrousos, George P.

National and Kapodistrian University

of Athens

che

grc

Chemical Engineering

Endocrinology &
Metabolism

Kalogirou, Soteris A.

Cyprus University of Technology

cyp

Energy

Yannakakis, Mihalis

Columbia University in the City of

usa

Computation Theory &

New York

Avouris, Phaedon

IBM Thomas J. Watson Research Center

Lyketsos, Constantine G.

Johns Hopkins Bayview Medical Center

Argyropoulos, Dimitris S.

NC State University

Giannakis, Georgios B.

University of Minnesota Twin Cities

Davatzikos, Christos

University of Pennsylvania

usa

Mathematik

Applied Physics

Geriatrics

Forestry

Networking &

Telecommunications

Nuclear Medicine &
Medical Imaging

Karniadakis, George Em

Brown University

usa

Applied Mathematics

32809

U Athens

56292

69452

Aristotle U

U Athens

188556

Higher

Tech Inst

16762

NTUA

226884

Aristotle U

9246

Northwestern

24339

U London

162693

NTUA

84992

NTUA

16040

MIT

C
Ö
M
P
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H
e
N
S
ich
v
e
M
A
P
P
ich
N
G

Ö
F

l
Ö
C
A
l

A
N
D

D
ich
A
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A

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N
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T
S

* Rank among all scientists in the same subfield, regardless of whether they are alive or deceased. Zum Beispiel, in General & Internal Medicine the top ranked scientist is Douglas Altman,
who is deceased. Also of note, the top 32 scientists who are highly ranked based on the percentile in their subfield (not shown here) include 23 of the 32 who are top-ranked based on the
absolute threshold (top 15 in the subfield).

** Number of scientists in the same subfield, including both those who are alive and those who are deceased; it is not straightforward to identify how many are deceased. The count includes
those who have at least five papers (articles, Bewertungen, or conference proceedings) indexed in Scopus and who have some papers classified in one of the 174 Science Metrix subfields.

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2
3

7
4
7

Comprehensive mapping of local and diaspora scientists

Botany, Fisheries, Sport Sciences, Environmental Sciences, Agronomy & Landwirtschaft, Dairy &
Animal Science, Entomology, Ornithology, History of Science, Technologie & Medicine,
Horticulture, Folklore). Umgekehrt, In 32 subfields, scientists outside of Greece exceeded by more
als 2: 1 scientists with affiliation in Greece (Cultural Studies, Law, Criminology, Communication
& Media Studies, Art Practice, Geschichte & Theory, Economic Theory, Automobile Design &
Maschinenbau, Development Studies, General Chemistry, Social Work, Developmental Biology,
Philosophy, Experimental Psychology, History of Social Sciences, Behavioral, Wissenschaft &
Comparative Psychology, International Relations, Psychoanalysis, Social Sciences Methods,
Aerospace & Aeronautics, Human Factors, Developmental & Child Psychology, Applied Ethics,
Anthropology, General Psychology & Cognitive Sciences, Social Psychology, Religions &
Theology, Physiology, Literary Studies, Musik, Clinical Psychology, Optics, Geschichte).

3.3. Top-Cited Greek Scientists Across Different Fields

Thirty-two Greek scientists were among the top 15 of their scientific subfield based on a cita-
tion indicator excluding self-citations (Tisch 3). Almost all of them (30/32, 94%) were listed by
Scopus with an affiliation outside of Greece. Of the 32 Wissenschaftler, information on place of birth
could be found on 28 (except for Terzopoulos, Stamatakis, Pavlou, and Argyropoulos); three
were born in Cyprus (Nicolaides, Nicolaou, Kalogirou), three were born in the United States
(Ioannidis, Joannopoulos, Alivisatos), one was born in the United Kingdom (Lyketsos), und das
remaining 21 had been born in Greece. Of the 32, 18 had received their first degree from an
institution in Greece.

4. DISKUSSION

We have created and validated a database of scientists of Greek origin that may be helpful for
evaluation, planning, and research policy purposes. It may also serve as a template for similar
efforts to be undertaken for other countries to map their scientific workforce. The iterative ap-
proach that we followed may also have special added value for countries that have sustained
heavy brain drain and/or that have a substantial scientific diaspora. The sensitivity and spec-
ificity achieved from such an approach in constructing scientist databases from different coun-
tries may vary depending on how unique first and last names are to geographic origin.

Our approach has tried to identify scientists originating from Greece regardless of their pres-
ent or past affiliations. We have also probed the sensitivity and specificity of the database
membership. The database is dependent on Scopus coverage, so scientists in fields not well
covered by Scopus may be particularly underrepresented. The database includes close to
64,000 author ID files representing scientists who have published at least five papers. Gegeben
that some scientists have their publications split in more than one file, the database probably
includes close to 60,000 unique scientists. Validation exercises suggest that it probably misses
very few scientists who meet the productivity eligibility criteria and who have an affiliation in a
Greek institution. Umgekehrt, a more substantial proportion has been missed among those
who have an affiliation in an institution outside of Greece. The estimate of the missingness
in this regard varies according to different validation sets that we used. Based on scientists
working abroad who on their own initiative offered to be included in a database of Greek
Wissenschaftler, about one in four scientists were missed with our approach. The percentage of miss-
ingness was higher based on a Wikipedia list of diasporeans, and even more when extending
beyond first-generation emigrants. It is unavoidable that our approach would miss Greeks who
acquire non-Greek names (upon second and subsequent generations) and for people who
change their names (z.B., through marriage, by making the name less foreign-sounding in their

Quantitative Science Studies

748

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0
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2
3

Comprehensive mapping of local and diaspora scientists

new country, or other reasons) and those who have a Greek last name that was not among the
ones we searched for. Some of these individuals may still be captured if they possess a highly
Greek-specific first name among the list of first names that we screened for. daher, sogar
though scientists with an affiliation in Greece were a slight majority in the compiled database,
Greek origin scientists with an affiliation outside of Greece would probably be the majority if all
Greek origin scientists could have been retrieved. The total of Greek origin scientists meeting the
productivity eligibility criteria may be in the range of 80,000–100,000 (~1.00–1.25% of the
global total). Umgekehrt, a few scientists are included in the database by failed disambiguation.
The validation process suggests that this situation is probably very uncommon.

The database reflects the large extent of general emigration from Greece as well as the massive
brain drain that the country has sustained over the years, with accelerated rates in the last decade in
conjunction with the economic crisis that hit Greece worse than almost any other highly developed
country. We noted that the cohort of scientists with affiliation outside of Greece had on average
younger publication ages, as revealed by the year of their first paper; half of them published
their first paper in 2004 or more recently.

While citation indicators are quite high for the entire database averages, scientists with an
affiliation outside of Greece have substantially stronger citation indicators and higher rankings
in their fields compared with scientists with affiliation in Greece. The difference is more prom-
inent among top-cited scientists, Wo 86% of the Greek origin scientists who are in the top
0.1% of their subfield are not in Greece. Ähnlich, almost all (94%) of the Greek origin scien-
tists who are among the top 15 of their subfield are not in Greece. Of interest, is that the large
majority of these extremely highly cited scientists were born in Greece, and the majority also
received their first degree in Greece. This further demonstrates the power of the brain drain
Verfahren. Gleichzeitig, scientists who have remained in Greece still include large numbers
placed in the top 20% of their subfield. Daher, the local scientific workforce still has consider-
able capacity for excellence. Of note, given our search strategy, is that our database has prac-
tically 100% sensitivity for Greek scientists abroad who are in the top 2% of citation impact,
while several scientists with lesser impact may have been missed.

The database includes scientists scattered across almost every scientific subfield. Scientists
with an affiliation in Greece have stronger concentrations than those with affiliations outside
of Greece in many fields of clinical medicine, several fields of biology, and agriculture/
fisheries/forestry. Greece has one of the highest rates of physicians per population in the
Welt, if not the highest (country-level data on medical doctors per 10,000 population are
verfügbar unter https://www.who.int/data/gho/data/indicators/indicator-details/GHO/medical
-doctors-per-10-000-population). Many of them are engaged in research, authoring or
coauthoring papers, as scientific publications are requested and appraised not only for
academic track positions, but even for regular clinical positions in the national health system.
The advantage is that these incentives create a large pool of physicians with exposure to
Forschung. The disadvantage is that much of this research may not be of high quality and these
authors have no lasting commitment to research. The concentration in subfields of agriculture,
fisheries, and biology is probably explained by the nature of the economy, although agricul-
ture and related fields have shrunk in latest years. Umgekehrt, there are several other fields
where most scientists of Greek origin do not work in Greece. This pattern is particularly strong
in the social and economic sciences and some cutting-edge biomedical sciences, wie zum Beispiel
developmental biology.

Some limitations need to be discussed. Erste, as we have already acknowledged, the data-
base is still missing several Greek origin scientists, in particular among those living and

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working abroad. We encourage people to provide relevant information at www.drosatos.com
/greekscientists to bring such cases to our attention. While it is impossible to update the da-
tabase by adding one more scientist at a time, collecting information on missing individuals
may allow us to consider further optimized automated processes in the future. While this pa-
per was in peer review, and as of March 20, 2021, 13 additional names of Greek scientists
were provided to us, but seven of those were already included in the database, two had fewer
than five papers by early 2020, and only four had been missed (Anna-Bettina Haidich
[Aristotle U Thessaloniki, h = 29], Elias Franses [Purdue, h = 36], Iosif Koutagiar [Hygheia
Hospital, h = 9], and Christos Chinopoulos [Semmelweis Egyetem, h = 31]).

Zweite, the constructed database was restricted to scientists with at least five full papers. In
the entire Scopus database, roughly four-fifths of author ID files have fewer than five papers.
Some of the author ID files with sparse papers may be split-off fragments of the publication
corpus of authors represented by some larger file. Trotzdem, by extrapolation, the total
number of Greek authors who have published at least one paper may be in the range of
250,000–500,000. The overwhelming majority of authors of 1–4 papers are not major contrib-
utors or leaders in the scientific enterprise. Jedoch, many young scientists in this group may
become major contributors or leaders in the future. daher, follow-up updates would be
useful to perform.

Dritte, Fehler (either splitting the same author into two or more author ID files or including
some papers by two or more authors in the same file) and inaccuracies in affiliations are possible.
Authors who recognize errors should contact Scopus directly to make these corrections in
Scopus itself, so that they may be carried over in our database with any potential future updates.
The entire Scopus database currently has overall 98.1% precision (proportion of papers in an
author ID file that belong to the author) Und 94.4% recall (proportion of papers of an author
included in the largest profile) (Baas et al., 2020). Precision and recall may be even better for
Greek-name authors, because Greek names are more rare and thus more specific than those of
most other origins (z.B., the disambiguation challenges for “Liu Wang” are greater than for
“Yiannis Triantafyllou”). We found 8.5% of the authors in the database to have a split profile
Und, given that even when one profile carries the large majority of the author’s papers, recall
probably substantially exceeds 94.4% for our database.

Vierte, allocation of fields and subfields follows a well-established classification, but some
scientists may have an almost equal number of papers in two or more fields, and the most
common one may not fully capture their expertise. Their ranking would have been different
had they been classified in a different subfield. Darüber hinaus, even within the same subfield, Dort
are granular subsections with different citation densities.

Fünfte, allocation of affiliation and country is performed automatically by Scopus picking just
one affiliation from the most recent papers of each author. Some authors have multiple current
affiliations, and some may have changed their affiliation recently. Wieder, we encourage au-
thors who want to change their listed affiliation to communicate directly with Scopus.
Misclassification may affect some authors in their classification as being in Greece versus out-
side of Greece. Jedoch, it would have been extremely difficult to curate affiliations manually
and it is impossible for an outsider to know which of many affiliations an author may prefer.

Sixth, our database does not automatically distinguish between first, zweite, and higher
generation emigrants. If deemed desirable, this would have to be done manually, und es
may have implications for policy (not losing scientists versus attracting scientists). Zweite
and higher generation emigrants are not necessarily a sign of brain drain, as they did not
emigrate themselves.

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Endlich, all citation metrics have limitations and they should be used with caution and not
as absolute indicators (Hicks, Wouters et al., 2015; Waltman, 2016; Wang, Veugelers, &
Stephan, 2017). We made no effort to assess the quality of the published works. Some authors
may rank high, but may have other reasons for concern (z.B., retracted papers, or implausibly
high self-citation metrics or evidence for citation farms). These need to be carefully scrutinized
on a case-by-case basis.

Acknowledging these caveats, the compiled database offers a tool that may be useful for both
research and policy purposes. For a country that is trying to recover from a lengthy economic crisis
and a superimposed crisis from the recent COVID-19 pandemic, realization of its scientific poten-
tial, deceleration and reversal of the brain drain and informed decision-making in the interface of
science and society may offer substantial added value. The brain drain and diaspora do not need to
have negative consequences for the home country; mapping of the scientific workforce and dias-
pora may help to maximize positive impact (Davenport, 2004; Wagner & Jonkers, 2017).

We also hope that the iterative approach used here may be applied also to map the scientific
workforce and scientific diaspora of other countries/nations as well. Scopus data can readily
identify scientists with affiliation in a given country. In the case of Greece, where few scientists
immigrate to from other countries, almost all scientists with affiliation in Greece have Greek
Namen. This would not be true for countries that attract many scientists from other countries,
but usually it is more important to map the entire scientific workforce rather than just native sci-
Entisten. The ability to map the diaspora of different countries depends on whether there are many
first and last names that are country-specific. Specificity may vary substantially across countries
and careful validation and cross-checking procedures should be applied accordingly.

BEITRÄGE DES AUTORS

John P. McCarthy. A. Ioannidis: Konzeptualisierung, Formale Analyse, Untersuchung, Methodik, Project
administration, Aufsicht, Validierung, Visualisierung, Schreiben – Originalentwurf, Schreiben-
Rezension & Bearbeitung. Chara Koutsioumpa: Datenkuration, Untersuchung, Validierung, Schreiben-
Rezension & Bearbeitung. Angeliki Vakka: Datenkuration, Untersuchung, Validierung, Schreiben – Rezension
& Bearbeitung. Georgios Agoranos: Datenkuration, Untersuchung, Validierung, Schreiben – Rezension &
Bearbeitung. Chrysanthi Mantsiou: Datenkuration, Untersuchung, Validierung, Schreiben – Rezension &
Bearbeitung. Maria Kyriaki Drekolia: Datenkuration, Untersuchung, Validierung, Schreiben – Rezension
& Bearbeitung. Nikos Avramidis: Datenkuration, Untersuchung, Validierung, Schreiben – Rezension & Bearbeitung.
Despina G. Contopoulos-Ioannidis: Datenkuration, Formale Analyse, Untersuchung, Validierung,
Visualisierung, Schreiben – Rezension & Bearbeitung. Konstantinos Drosatos: Konzeptualisierung, Data cura-
tion, Untersuchung, Projektverwaltung, Aufsicht, Validierung, Schreiben – Rezension & Bearbeitung.
Jeroen Baas: Konzeptualisierung, Datenkuration, Formale Analyse, Untersuchung, Methodik,
Ressourcen, Software, Validierung, Schreiben – Rezension & Bearbeitung.

COMPETING INTERESTS

Jeroen Baas is an employee of Elsevier, which runs Scopus.

FUNDING INFORMATION

No funding has been received for this research.

DATA AVAILABILITY

All the data on the 63,951 scientists are available in Mendeley at https://doi.org/10.17632
/zbyctscmbn.1.

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