ARTÍCULO DE INVESTIGACIÓN
Comparing institutional-level bibliometric research
performance indicator values based on different
affiliation disambiguation systems
Paul Donner1
, Christine Rimmert2, and Nees Jan van Eck3
1German Centre for Higher Education and Research Studies, DZHW, Berlina, Alemania
2Bielefeld University, Alemania
3Centre for Science and Technology Studies, Universidad de Leiden, Países Bajos
Palabras clave: research evaluation, institution name disambiguation, bibliometric data, data quality,
Web of Science, Scopus, validation study
ABSTRACTO
The present study is an evaluation of three frequently used institution name disambiguation
sistemas. The Web of Science normalized institution names and Organization Enhanced
system and the Scopus Affiliation ID system are tested against a complete, independiente
institution disambiguation system for a sample of German public sector research organizations.
The independent system is used as the gold standard in the evaluations that we perform. Nosotros
study the coverage of the disambiguation systems and, En particular, the differences in a
number of commonly used bibliometric indicators. The key finding is that for the sample
institutions, the studied systems provide bibliometric indicator values that have only a limited
exactitud. Our conclusion is that for any use with policy implications, additional data
cleaning for disambiguating affiliation data is recommended.
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1.
INTRODUCCIÓN
Scientometric studies at the level of research institutions face the challenge of the correct at-
tribution of publications to institutions. This task, here referred to as institution name disam-
biguation, comprises systematically standardizing the heterogeneous address data of the
author-provided affiliation information present in publications and recorded in bibliographic
bases de datos. Actualmente, institutional affiliation information in academic publications is not stan-
dardized and unique identifiers for research institutions have not yet been adopted. Por lo tanto,
in order to generate valid primary data on publications for studies at the meso level, the as-
signment of address strings to known real institutional entities is crucial. Institution name dis-
ambiguation belongs to a class of problems known as named entity normalization, en el cual
variant forms have to be matched to the correct preferred form. Another prominent member of
this class is author name disambiguation. Disambiguated affiliation information can contribute
to the performance of author name disambiguation systems that employ affiliations as back-
ground information.1
In the recent past, a nearly complete institutional disambiguation for German research in-
stitutions was developed and implemented at the Institute for Interdisciplinary Studies of
1 Asimismo, disambiguated author information could potentially be used as additional input information for
institutional disambiguation. Sin embargo, we are not aware of any literature on this approach.
un acceso abierto
diario
Citación: Donner, PAG., Rimmert, C., &
van Eck, norte. j. (2020). Comparing
institutional-level bibliometric research
performance indicator values based on
different affiliation disambiguation
sistemas. Estudios de ciencias cuantitativas,
1(1), 150–170. https://doi.org/10.1162/
qss_a_00013
DOI:
https://doi.org/10.1162/qss_a_00013
Recibió: 15 Abril 2019
Aceptado: 04 Noviembre 2019
Autor correspondiente:
Paul Donner
donner@dzhw.eu
Editor de manejo:
Vincent Larivière
Derechos de autor: © 2020 Paul Donner,
Christine Rimmert, and Nees Jan
van Eck. Published under a Creative
Commons Attribution 4.0 Internacional
(CC POR 4.0) licencia.
La prensa del MIT
Comparing institutional-level bibliometric research performance indicator values
Science at Bielefeld University, as a major component of a national bibliometric data infra-
structure for research and monitoring (Rimmert, Schwechheimer, & Winterhager, 2017).
The system has been tested and improved over a number of years and is now in production
usar. We are therefore in a position to study the degree to which the use of a sophisticated
disambiguation system with near-complete national-scale coverage leads to different biblio-
metric indicator values compared to a situation in which no such system is available and sim-
pler alternatives to the attribution problem have to be used. We consider here (a) the case
where a simple unification strategy using ad hoc lexical searches in the address data fields
of a bibliographic database is conducted in order to collect publications of the target institu-
ciones (based on vendor preprocessed affiliation data in Web of Science [WoS]); y (b) the use
of bibliographic database vendors’ own institution disambiguation systems (in both WoS and
Scopus). We believe that these two situations are common in practice outside of specialized
research or evaluation units with access to the raw data of bibliographic databases. The per-
formance and implications of these approaches are therefore relevant and of wide interest to
the bibliometrics and research evaluation communities. Prominent examples with profound
science-political consequences of the use of bibliometric data of institutions derived from
WoS or Scopus are the international university rankings, which generate much public atten-
tion and elicit considerable debate.
The remainder of the article is structured as follows. We begin by providing an overview of
the prior work on institutional disambiguation. Próximo, we briefly outline the institution name
disambiguation systems that we study and describe the publication data and institution
samples that we use, as well as the comparison scenarios, the bibliometric indicators that
are calculated for the institutions, and our approach of assessing the differences in indicator
valores. In the next section we present the results of our comparisons. En particular, we assess
the distributions of errors in indicator values over institutions arising when applying alternative
disambiguation systems in contrast to the reference values obtained from the presented dis-
ambiguation system for German research institutions, which can be assumed to be complete
and nearly error free for the data. The results and their implications are summarized in the
Discussion section.
2. RELATED WORK
Unification of author affiliation information and the allocation to clearly identified research
institutions has been recognized as a challenging task in the bibliometric research community
and beyond. Accurate disambiguation of heterogeneous affiliation data is crucial for institution-
level scientometric research and bibliometric evaluation. Disambiguation systems connecting
heterogeneous author affiliations to known research institutions have been constructed in sev-
eral projects—usually for project-specific purposes and not to be made available publicly.
They may be roughly divided into rule-based and machine learning approaches. Sin embargo,
this division is not a strict one, as approaches often use combinations of methods (p.ej., normas
and some manual work are used in addition to a machine learning approach to improve pre-
decisión, especially for problematic cases).
2.1. Rule-based Approaches
A substantial amount of work on this topic has been done at the Centre for Science and
Technology Studies (CWTS) at Leiden University. For the case of universities, this began with
De Bruin and Moed (1990). They performed a unification of about 85,000 affiliations from 75
journals (data from SCISEARCH) using the first part of the addresses. Using structural
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Comparing institutional-level bibliometric research performance indicator values
information and reference books, they assigned units on lower hierarchical levels (p.ej., depart-
mentos), appearing in the first part of addresses, to the corresponding main organization. Ellos
found that many problems remained, and to solve these they used external information from
encyclopedias, university handbooks, specialists, and staff lists of universities. This is a time-
consuming method, and they only did this for selected countries (in particular the
Países Bajos). In a follow-up study, Moed, De Bruin, and Van Leeuwen (1995) reported on
a bibliometric database constructed from all articles published by authors from the
Netherlands using data from the Science Citation Index. To store unified affiliations, they im-
proved their earlier procedure for Dutch addresses by, among other things, adding a classifi-
cation of institutions to research sectors: eso es, types of organizations such as universities,
hospitals, and firms. They noted problematic affiliations that could not be handled correctly
by their procedure. CWTS continued to maintain and improve its disambiguation system, en
particular for its university ranking, for which all name variants that occur at least five times in
the WoS are cleaned (Waltman et al., 2012). This system pays special attention to the way
publications by academic hospitals are assigned to universities (Reyes-Elizondo, Calero-
Medina, Visser, & waltman, 2016).
The Swedish Research Council performed affiliation disambiguation for its bibliometric da-
tabase, which was also constructed based on WoS data (Kronman, Gunnarsson, & Karlsson,
2010; Swedish Research Council, 2017). They used a deterministic approach based on a cat-
alog of string rules, mapping address strings to 600 known Swedish research organizations.
Organizations were also classified by the research sector. Their procedure was able to assign
encima 99% of Swedish address strings. A single address may be matched to more than one or-
ganization in the case of affiliations containing information on more than one organization,
usually indicating collaborations.
2.2. Machine Learning Approaches
Francés, Powell, and Schulman (2000) described a number of institutional disambiguation ex-
periments with different address string distance metrics and a one-pass heuristic clustering pro-
cedure. The clearly stated goal was not a complete automatic disambiguation, but rather the
reduction of manual reviewing of the most difficult cases. Among other things, they introduced
un nuevo, domain-specific affiliation comparison function, based on normalized and sorted
palabras, minimizing edit distances between aligned words across possible permutations.
Jonnalagadda and Topham (2010) reported on their disambiguation of institution names ex-
tracted from PubMed data. The presented approach utilized agglomerative clustering, para
which the entity similarity is computed with an edit distance, building on the work of
French et al. (2000). En particular, their approach was a hybrid of a sequence alignment mea-
sure over word sequences (Smith–Waterman algorithm) and the Levenshtein distance between
single words. Además, similar clusters were merged. They reported sample precision
values of 99.5% (4,135 affiliation strings related to “Antiangiogenesis,” only US organizations)
y 97.9% (1,000 affiliation strings related to “Diabetes,” organizations from any country) para
organization normalization. Although these values are high, it is not possible to extrapolate
them to less restricted data sets. Galvez and Moya-Anegón (2006, 2007) reported on a new
approach using finite-state graphs, developed with WoS data and also tested on data from
Inspec, Medline, and CAB Abstracts. Although this is a promising approach, the authors out-
lined the limits of automatic classifications for problematic affiliations, which requires expert
knowledge to classify. Jiang, Zheng, Wang, Lu, and Wu (2011) discussed an experimental ap-
proach of agglomerative clustering of affiliations using string compression distance. Their eval-
uation of the method is questionable, as they use the publication affiliations of mostly students
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Comparing institutional-level bibliometric research performance indicator values
and staff from a single university. Their affiliation string pool is, por lo tanto, dominated by name
variants of that university, although the remainder are affiliations of coauthors. They extracted
a reference corpus of 217 “affiliations” (variants) de 105 “categories” (true organizations). En
any case, their clustering quality results are not encouraging. This also holds true for the ap-
plication of supervised and semisupervised machine learning methods, tested by Cuxac,
Lamirel, and Bonvallot (2013) on French CNRS addresses. Huang, Cual, yan, and Rousseau
(2014) proposed an algorithm using author information to classify affiliations that received high
precision values but low recall.
We can conclude that the problem of institution name disambiguation is far from being
solved. For the objective of achieving highly accurate disambiguation, it seems that simple
methods have not yet been replaced by fully automatic methods, despite the experimental
application of several sophisticated approaches with partly promising results on small scales.
Sin embargo, significant progress has been made on affiliation string similarity calculation
methods. Both rule-based and machine learning methods can be used to minimize the nec-
essary amount of manual human decisions. Sin embargo, the necessarily higher amount of
labor required by rule-based methods means that they have only been applied to parts of
all author affiliations, typically to those from one country or discipline. No standard evaluation
data set is available for this task. Además, none of the studies have investigated the effects
of institutional disambiguation on the quality of bibliometric indicator scores.
3. SYSTEMS, DATA, AND METHODS
3.1.
Institution Disambiguation Systems
In this section we summarize the disambiguation system that was developed for German in-
stitutions. For a full description of the system we refer readers to Rimmert et al. (2017). El
sistema, which we call the KB system,2 is comprised of (a) a set of known and uniquely iden-
tified German research institutions, (b) a mapping of institutions to affiliation records identified
as belonging to each institution from the two data sources WoS and Scopus, (C) a hierarchical
classification of the institutions into sectors, y (d) a change history of the institutions which
record the splitting and merging and incorporation of institutions and sector changes. The KB
system is thus built on the affiliation data provided in WoS and Scopus, respectivamente, y se-
longs to the category of rule-based systems. The tracking of structural changes affords the nec-
essary flexibility in handling such changes required by different project contexts. In the KB
sistema, two different analytical views are implemented (item 4 arriba). With Mode S (for syn-
chronic allocation), we can perform analyses that take into account the institutional structures
as they were at the time of publication for each paper. Institutions that have later come to be
related to another institution through structural changes, such as through mergers or splits, son
treated as different entities. Por otro lado, with Mode A (asynchronic, current perspec-
tivo), we can analyze the publication records of institutions as they are constituted at present;
eso es, including publications of predecessor units. The mapping of institutions to affiliation
records (item 2 arriba) is a deterministic, rule-based classification. The core of the institutional
coding procedure is a mapping of author addresses to the corresponding uniquely identified
research institutions and their subdivisions, using a large library of regular expressions. Este
library currently contains some 45,000 expressions and is continuously being expanded
and improved.
2 The system was created in a project called Kompetenzzentrum Bibliometrie (Competence Centre for
Bibliometrics).
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Comparing institutional-level bibliometric research performance indicator values
The sector classification (item c above) contains the classes of higher education sectors
(universities and universities of applied sciences), four major nonuniversity research organiza-
ciones (Fraunhofer-Gesellschaft [FHG], Helmholtz Association [HGF], Leibniz Association
[WGL], and the Max Planck Society [MPG]), private companies, registered associations, gobierno-
ernment laboratories, and academies of science. For the sector information, structural changes
over time and multiple assignments of research institutions to these sectors are also available.
The version of the KB system used for this study contained 2,097 institutions, which also
included placeholder records for unidentified institutions for which only the sector could be
determined. An evaluation of the KB disambiguation system was conducted prior to the main
estudiar. We provide a detailed overview of the system evaluation in Appendix A for German
research institutions. We conclude that, based on the good results of this evaluation, the KB
system is a valid, gold standard benchmark for German institutional affiliation disambiguation
datos. This is not to say, sin embargo, that the KB system or its rule-based approach are superior in
general. De hecho, its scope is limited to a single country and it would be difficult to extend the
method to global scope because of the large effort and unreasonable expense required.
We deliberately do not attempt to describe the workings of the proprietary institution dis-
ambiguation systems of WoS and Scopus and regard them as black boxes, of which we only
analyze the results. The reason for this is that both systems are not documented in any detail by
the providers. What we can gather from the information of the platforms is that WoS
Organizations Enhanced (OE) is based on lists of variant names mapped to preferred names.3
WoS OE can therefore be seen as a rule-based system. Regarding the Scopus Affiliation
Identifiers (AFIDs), the documentation merely informs us that “the Affiliation Identifier distin-
guishes between affiliations by assigning each affiliation in Scopus a unique number, y
grouping together all of the documents affiliated with an organization.”4 No information is
given about how the system works.
3.2. Datos
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The data used in the analyses are derived from the licensed source of WoS5 and Scopus, transmisión exterior-
tained in spring 2017. The data were loaded into in-house relational databases, cleaned, y
enhanced at the Competence Centre for Bibliometrics for Germany. The most important en-
hancement is the disambiguation of German author addresses to known German research
institutions. This process is conducted separately for each data source using the KB disambig-
uation system described in the previous subsection. The units of the analysis for this study are
German academic institutions, in particular universities, universities of applied sciences, y
nonuniversity research institutes. Publications are restricted to articles and reviews published
entre 1995 y 2017. To be included, an institution needed to have at least 50 semejante
publications associated with it according to the KB disambiguation of the WoS data. Estos
restrictions resulted in a study sample of 445 institutions. The same institutions are used to
investigate both WoS and Scopus.
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3 https://clarivate.libguides.com/woscc/institution; http://ips.clarivate.com/m/pdfs/UnifyingNameVariants.pdf,
accessed April 13, 2018.
4 https://service.elsevier.com/app/answers/detail/a_id/11215/supporthub/scopus/related/1, accessed April 13,
2018.
5 The WoS data used in this study include data from the Science Citation Index Expanded, the Social
Sciences Citation Index, las artes & Índice de citas de humanidades, and the Conference Proceedings Citation
Index.
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Comparing institutional-level bibliometric research performance indicator values
3.2.1. Scopus AFID
For the Scopus data, we compare the KB system-derived reference data to sets of publications
that have one or more common assigned AFIDs (affiliation identifiers), as provided by Elsevier.
Some preprocessing steps to align the Scopus and KB disambiguation systems were performed
in order to make them comparable, as they are conceptually and structurally somewhat dif-
ferent. To match AFIDs to the KB system IDs, the AFID for each institution in our sample was
obtained by searching Scopus’s online platform. It is not clear whether and how exactly the
definition of an institution in Scopus differs from the one the KB disambiguation is based on.
One difference that we have noticed is that the AFID system typically has separate IDs for
university hospitals and the universities they belong to, which is not the case in the KB system.
We have therefore merged those AFIDs to create more comparable and consistent publication
record sets. Además, in some cases more than one AFID for the same institution exists in
Scopus, por ejemplo, for multiple branch locations. If these are logically linked in the hierar-
chical relations in the Scopus system, we also merged these linked AFIDs. If not, we took only
the most commonly used AFID per institution.
We found that in the AFID system, publications with affiliations referring to predecessor
units are grouped with their current unit. Based on this observation, we compare the AFID
results with those from the KB system’s Mode A.
3.2.2. Web of Science (WoS) organization enhanced
The WoS OE system does not have unit identifiers but Preferred Names, which are additionally
assigned as institution names to affiliations considered belonging to one real institution. In or-
der to identify the WoS Preferred Name for the institutions in our set, we started by identifying
all the Preferred Names of records with German addresses that occur more than 20 veces.
From this list, we chose the Preferred Name matching the target institution and otherwise ex-
cluded the institution from this part of the study. De hecho, for our sample set, it was not possible
to retrieve the corresponding publications on the main institutional level in a majority of cases.
Although many universities are recorded in OE, the institutions of FHG, HGF, WGL, and MPG
are almost all grouped such that only all publications of each of the respective head organi-
zations can be found, but rarely those of their member institutes.6
Similar to AFID, also in the WoS OE system, predecessor units are grouped under the
Preferred Name of the current institution. En consecuencia, we also compare the WoS OE
system with Mode A of the KB system.
3.2.3. WoS institution name search
As well as the comparison of WoS OE data with the KB disambiguation, we also investigated
the performance of a lexical search using the institution name in the WoS affiliation data. Como
pointed out above, the coverage of institutions in the WoS OE system is far from complete
(since only head organizations are covered, not their member institutes), which supports the
notion that such an alternative approach might often be required in practice. The institution
name search method makes use of WoS disambiguation efforts, because institution names ex-
tracted from affiliation information in papers are not indexed identically to how they are given
in the original publication but are normalized. Because the affiliations in Scopus are not
6 After reaching out to Clarivate Analytics for comments, we were informed that the decision to include the
MPG as a whole but not its member institutes was based on a request by MPG. The same approach was then
also taken for the other nonuniversity research organizations.
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Comparing institutional-level bibliometric research performance indicator values
transformed or normalized, we do not apply a similar search strategy to Scopus data. De hecho, él
is not possible to conduct comparable searches across these two databases because WoS only
contains normalized address strings, while Scopus only contains the original address strings.
In this scenario, we model a hypothetical user who has a list of the names of the German
research institutions available, which is used as a basis for generating search terms. Nosotros también
assume that the user is familiar with searching in WoS data to a sufficient degree. This scenario
further requires a definition of the name list, the search terms, and the search parameters.
In order to generate a plausible name list, we begin by using the KB institutional disambig-
uation results to find the most common normalized name in the WoS data for each real insti-
tution in our initial set, because in principle there should be only one normalized name for
Mesa 1. Overview of selected bibliometric indicators
Domain
Publication output
Indicator
PAG: Number of publications (full count)
Collaboration
PAG(collab): Number of collaborative
publicaciones
PÁGINAS(collab): Proportion of collaborative
publicaciones
PAG(int collab): Number of international
collaborative publications
PÁGINAS(int collab): Proportion of international
collaborative publications
Citation impact
TCS: Total citation score
MCS: Mean citation score
Observaciones
The number of publications of an institution
The number of an institution’s publications
that have been coauthored with one or
more other institutions
The proportion of an institution’s publications
that have been coauthored with one or
more other institutions
The number of an institution’s publications
that have been coauthored by two or
more countries
The proportion of an institution’s publications
that have been coauthored by two or
more countries
The total number of citations of the
publications of an institution
The average number of citations of the
publications of an institution
TNCS: Total normalized citation score
The total number of citations of the
publications of an institution, normalized
for field (WoS: Subject Category; Scopus:
ASJC) and publication year
MNCS: Mean normalized citation score
The average number of citations of the
PAG(arriba 10%): Number of highly cited
publicaciones
PÁGINAS(arriba 10%): Share of highly cited
publicaciones
publications of an institution, normalized
for field (WoS: Subject Category; Scopus:
ASJC) and publication year
The number of an institution’s publications
eso, compared with other publications
in the same field and the same year, belong
to the top 10% most frequently cited
The proportion of an institution’s publications
eso, compared with other publications in
the same field and the same year, belong
to the top 10% most frequently cited
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Comparing institutional-level bibliometric research performance indicator values
Mesa 2. Coverage of sample institutions by the studied disambiguation systems
Sector
Fraunhofer-Gesellschaft
Helmholtz Association
Max Planck Society
Universities
Leibniz Association
Universities of applied sciences
Total
Number of institutions Covered in WoS OE Covered in WoS search Covered in Scopus AFID
62
23
86
107
83
90
445
1
9
0
66
8
9
91
62
23
86
107
83
90
445
57
16
78
96
56
75
376
Nota. The figure in the row “Total” may differ from the sum of the above cells because some institutions are assigned to more than one sector.
each institution. We manually assess the lists side by side with the real names and discard any
WoS name that cannot be deduced from the name list, using instead the next most common
name variant iteratively until all WoS normalized names are mapped to KB system IDs based
on the names in the two systems. This relates to our decision of going beyond a completely
naïve and automatic procedure and including a realistic degree of user common sense and
domain familiarity. We use the search term list thus obtained as retrieval inputs, while also
ignoring capitalization and allowing truncation at the end of the term, and searched the full
address information field. This came reasonably close to an informed, but nonspecialized,
search for an institution on the online platform of WoS. It is general in the sense that all insti-
tutions are treated in the same way and no special knowledge of affiliation idiosyncrasies is
incluido. It is limited in the sense that we only consider one name variant per institution.
Because we directly use the normalized affiliation data as it is indexed in WoS, it is clear
that we use the normalized versions of the institution names at the time of publication. De este modo,
we use Mode S of the KB system for comparison.
3.3. Métodos
To assess the performance of the studied systems in terms of being able to identify the correct
publications of the research institutions we use the information retrieval measures of precision
and recall. For this task, precision is calculated as the share of correctly retrieved publications
among the total number of retrieved publications. Recall is the share of correctly retrieved
publications among all relevant publications. The correct publications of an institution are
those identified by the KB system.
In order to quantify the effect of the application of a specific institutional disambiguation on
scores of bibliometric indicators, we calculated the indicator values based on the publications
of each institution as retrieved by the KB system—considered a validated gold standard for the
Mesa 3. Summary statistics of the distributions of precision and recall of retrieved publications per institution for WoS OE (norte = 91)
Precision
Recordar
Mínimo
0.41
0.07
Median
0.99
0.94
Arithmetic mean
0.96
Weighted mean
0.95
0.87
0.93
Máximo
1.00
0.99
Standard deviation
0.11
0.18
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Comparing institutional-level bibliometric research performance indicator values
Cifra 1. Precision and recall for WoS OE (norte = 91).
selected institutions in this study—and for each of the three alternative systems. The differ-
ences of indicator values are calculated, and the arising error distributions are displayed.
A number of commonly utilized bibliometric indicators are included in this study. Nosotros estafamos-
sider the three domains of publication output, colaboración, and citation impact. For the latter
two domains we have selected indicators that are size dependent (absolute numbers) también
as size-independent indicators (ratios or averages). The citation indicators are all calculated for
5-year citation windows which include the year of publication. The indicators are summarized
en mesa 1. It is clear that the size-dependent indicator values are directly related to the number
of correctly identified publications. Sin embargo, it might be hypothesized that the values of size-
independent indicators are less affected when only a part of the correct publication set is used
as their input, because errors may cancel each other out.
We compare two vendor-provided disambiguation system results and one search-based re-
sult with the KB system’s results, which we take as the correct result providing reference
valores. We divide the system evaluation into two parts. Primero, for each institution in the eval-
uation set, we would like to find all its publications, without retrieving any publications it was
not involved in. This is a basic information retrieval task, which can be measured with preci-
sion and recall. We also use retrieval performance, including the absolute number of retrieved
institutions in the evaluation set, to analyze the coverage of the systems with respect to our
sample of 445 institutions. The second component of the evaluation concerns the bibliometric
Mesa 4. Institutions with low recall for WoS OE
Institution Name (KB system)
Helmholtz-Zentrum für Infektionsforschung
WoS OE Preferred Name
Helmholtz Center Infectious Research
Hochschule Fresenius
Fresenius University of Applied Sciences
Fraunhofer-Institut für Optronik, Systemtechnik
Fraunhofer Optronics, System Technologies
und Bildauswertung IOSB
& Image Exploitation Ettlingen
Leibniz-Institut für Festkörper- und
Werkstoffforschung Dresden
Leibniz Institute Solid State & Materials Research Dresden
Estudios de ciencias cuantitativas
Recordar
0.07
0.15
0.16
0.18
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Comparing institutional-level bibliometric research performance indicator values
Mesa 5. Deviation of indicator scores of WoS OE from KB system (norte = 91)
Indicator
PAG
PAG(collab)
PÁGINAS(collab)
PAG(int collab)
PÁGINAS(int collab)
TCS
MCS
TNCS
MNCS
PAG(arriba 10%)
PÁGINAS(arriba 10%)
Percent deviation within ±5%
40.7
Median absolute deviation (%)
4.5
38.5
93.4
37.4
86.8
52.6
79.1
40.7
85.7
48.4
100.0
4.3
0.6
3.4
1.3
4.0
1.3
3.7
1.3
3.7
0.04
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indicator scores calculated from the retrieved institution publication sets. En general, the numer-
ical discrepancy between the indicator values, using the KB disambiguation (reference values)
and the other methods, will be expressed as relative deviation in percent, calculated as
deviation ¼ observed system score− KB system reference score
Þ=KB system reference score
d
(cid:2) 100
The deviation has a lower bound at −100% and is unbounded in the positive direction. Para
ejemplo, let the reference MCS of a unit be 5.5 (calculated based on the KB disambiguated
datos), and the focal value obtained from a simple institution search in WoS be 4.2. Then the
deviation as defined above is (4.2 − 5.5)/5.5 × 100 = −23.6%. En este caso, the correct result
would be underestimated by 23.6%.
For each indicator, the computed deviations for each institution are collected. Nuestro principal
measure of accuracy is the percentage of values within a range of ±5% of the reference score.
4. RESULTADOS
An overview of the coverage of German institutions in the WoS and Scopus institution disam-
biguation systems and the lexical search method in WoS is provided in Table 2. We are able to
find only 91 de nuestro 445 (20%) evaluation sample institutions in the OE system. The coverage of
OE is the lowest among the systems considered. To a significant extent, this is a consequence
of the choice not to include the member institutes of nonuniversity research organizations in
WoS OE. The set of covered institutions in WoS OE is comprised mostly of universities.
Sin embargo, also for the universities, in particular for the universities of applied sciences, a sig-
nificant number of institutions are not covered in WoS OE. Using the search strategy, podemos
find one normalized form for each institution, achieving complete coverage of the institutions.
The Scopus AFID system covers 376 (85%) of the institutions with no conspicuous differences
between sectors.
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Cifra 2. Distributions of indicator score deviations of WoS OE from KB system in Mode A. Diagonal lines indicate the ±5% error margin for
indicator values.
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Comparing institutional-level bibliometric research performance indicator values
Mesa 6. Summary statistics of distributions of precision and recall of retrieved publications per institution for WoS institution name search
(norte = 445)
Precision
Recordar
Mínimo
0.08
0.03
Median
0.69
0.51
Arithmetic mean
0.67
Weighted mean
0.61
0.55
0.74
Máximo
0.99
1.00
Standard deviation
0.19
0.26
4.1. WoS Organizations Enhanced
We present the institution-level figures for precision and recall for WoS OE in Table 3 y
Cifra 1. All results should be interpreted with due caution because of the OE system’s limited
coverage of the selected institutions. The precision of WoS OE for these institutional publica-
tion sets is 0.95, on average, across institutions, weighted by publication numbers. Por eso,
typically about 5% of the returned publications in a result set of a specific preferred name will
be false positives. The weighted mean of recall across institutions is 0.93, meaning that the
result sets do not include about 7% of relevant publications, on average. The contrast between
unweighted (0.87) and weighted mean for the recall shows that the results for larger institutions
(in terms of number of publication) are better than for smaller institutions. We found poor re-
sults for recall for the four institutions presented in Table 4.
We now turn to the results of the comparison of the scores of bibliometric indicators
between the WoS OE and the KB system. The results are presented in Table 5, in the form
of summaries of the deviation score distributions, visualized in Figure 2. It can be seen that
absolute indicator scores (number of publications, collaborative publications, and cita-
ciones) are less often within the range of nearly correct values (±5%) than relative indicator
puntuaciones.
4.2. WoS Institution Name Search
En esta sección, we compare the results of the WoS institution name search with those of the KB
sistema. Note that the search makes use of the institution name normalization of WoS, and we
Cifra 3. Precision and recall for WoS institution name search (norte = 445).
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Comparing institutional-level bibliometric research performance indicator values
Mesa 7. Institutions with low recall for WoS institution name search
Institution name (KB system)
Max-Planck-Forschungsgruppe Optik,
Information und Photonik
Leibniz-Institut für Katalyse e. V. an der
Universität Rostock (LIKAT)
Friedrich-Miescher-Laboratorium für biologische
Arbeitsgruppen in der Max-Planck-Gesellschaft
Berliner Elektronenspeicherring – Gesellschaft für
Synchrotronstrahlung mbH
Hochschule für angewandte Wissenschaft und
Kunst, Fachhochschule Hildesheim/Holzminden/Göttingen
Most common WoS normalized name
INST OPT INFORMAT & PHOTON
LEIBNIZ INST KATALYSE EV
FRIEDRICH MIESCHER LAB
BERLINER ELEKTRONENSPEICHERRING
GESELL SYNCHROTRO
HAWK UNIV APPL SCI & ARTS
Recordar
0.03
0.04
0.06
0.08
0.08
have deliberately searched for the single most common WoS normalized name per institution,
as mentioned above. Using this search method, we obtain vastly more institution publication
sets than using WoS OE; En realidad, full coverage of all sample institutions is achieved (ver
Mesa 2). The summary of the distributions of precision and recall is given in Table 6 y
the values are displayed in Figure 3. We obtain rather poor results for the average precision
de 0.61 when weighting institutions by the number of publications, y 0.67 as the arithmetic
significar. Publication sets for this method will often contain many publications incorrectly as-
signed to the institutions in question. Recall is at 0.74 weighted mean and 0.55 aritmética
significar, which means that the publication lists returned by these queries will commonly be in-
complete, but less so for the larger institutions. Tables 7 y 8 provide the five institutions with
the lowest recall and precision scores.
These results for recall suggest that the normalization procedure of WoS is often unable to
group most of the relevant institution name variants under one normalized form.
The results of the comparison of the bibliometric indicator scores between the WoS institution
name search approach and the KB system for Mode S are provided in Table 9 and the deviation
distributions are displayed in Figure 4. The shares of institutions for which the scores obtained with
the institution name search approach are within ±5% of the reference score are low, especialmente para
the absolute indicators. Dispersion of the deviations is high. Además, the ratio- and mean-based
citation scores are comparatively less inaccurate. Evidently, the incomplete publication list result
sets of this method lead to substantially inaccurate scores for all indicators.
Mesa 8. Institutions with low precision for WoS institution name search
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Institution name (KB system)
Max-Planck-Institut für Biologie
Max-Planck-Institut für Biophysik
Fraunhofer-Institut für Optronik, Systemtechnik
und Bildauswertung IOSB
Most common WoS normalized name
MAX PLANCK INST BIOL
Precision
0.08
MAX PLANCK INST BIOPHYS
FRAUNHOFER IOSB
ESCP Europe Wirtschaftshochschule Berlin e.V.
ESCP EUROPE
Forschungszentrum für Marine Geowissenschaften GEOMAR
GEOMAR
Estudios de ciencias cuantitativas
0.10
0.15
0.17
0.21
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Comparing institutional-level bibliometric research performance indicator values
Mesa 9. Deviation of indicator scores of WoS institution name search from KB system (norte = 445)
Indicator
PAG
PAG(collab)
PÁGINAS(collab)
PAG(int collab)
PÁGINAS(int collab)
TCS
MCS
TNCS
MNCS
PAG(arriba 10%)
PÁGINAS(arriba 10%)
4.3. Scopus AFID
Percent deviation within ±5%
6.7
Median absolute deviation [%]
52.5
7.2
29.0
10.1
20.5
10.8
9.9
5.7
52.0
7.6
13.7
45.4
12.5
45.2
17.9
39.6
18.8
55.5
6.6
46.6
14.7
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The results for precision and recall of the Scopus AFID system, under the Mode A condition,
are summarized in Table 10 and displayed in Figure 5. Precision is quite high, pero, in contrast,
recall is more moderate. De nuevo, we find that the weighted mean precision and recall are
slightly greater than the unweighted ones, suggesting that disambiguation quality is typically
a little better for larger institutions. We also note that the coverage of our selected benchmark-
ing institutions for the AFID system is 376 out of 445 (es decir., 85%) and therefore far from com-
plete. Unlike the WoS OE system, the Scopus AFID system is not largely concentrated on
universidades (Mesa 2). Mesa 11 provides the five institutions with the lowest recall scores for
the Scopus AFID system.
The direct comparison of the results for the indicator scores, calculated with the Scopus
platform disambiguation system—AFID—on the one hand, and those calculated with the
KB system on the other, in terms of distributions of percent deviation, are given in Table 12
and the deviation distributions are displayed in Figure 6. We find on average, for the absolute
indicators, considerable shares of scores that are outside the range of accepted values. Relativo
indicators scores are less severely affected, but not within the accepted range often enough to
be considered reliable. It is worth pointing out that in particular the total number of citations
(TCS) is rarely within the allowed range, cual, sin embargo, did not seem to overly affect the
other citation indicators.
5. DISCUSIÓN
We have investigated the accuracy of bibliometric indicator values for German publicly
funded research organizations that can be obtained through a search strategy on vendor-
normalized data (for WoS) and through the use of the database vendors’ proprietary institution
disambiguation systems (for both WoS and Scopus). These indicator values were compared
with results from a nearly complete and independent institutional disambiguation for which
detailed performance characteristics were provided.
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Cifra 4. Distributions of indicator score deviations of WoS institution name search from KB system in Mode S. Diagonal lines indicate the
±5% error margin for indicator values.
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Comparing institutional-level bibliometric research performance indicator values
Mesa 10. Summary statistics of the distributions of precision and recall of retrieved publications per institution for Scopus AFID (norte = 376)
Precision
Recordar
Mínimo
0.17
0.03
Median
0.96
0.90
Arithmetic mean
0.92
Weighted mean
0.96
0.82
0.86
Máximo
1.00
0.99
Standard deviation
0.10
0.20
During our study, we found that conceptual differences between the three institution dis-
ambiguation systems and a lack of documentation of both the WoS OE system and the
Scopus AFID system were obstacles to making straightforward comparisons. En particular,
the definition of the basic institutional entity—which is a crucial point for comparing disam-
biguation systems—varied among the systems. Por ejemplo, in Scopus, university hospitals
were kept separate from university entities. They had different AFIDs, which were not con-
nected in any way. This inhibits evaluations for universities including their academic hospi-
tals or medical faculties. For a comparison with the KB system, these entities, academic
hospitals and the universities to which they belong, had to be aggregated manually. Otro
issue was faced regarding the handling of predecessor institutions. In order to obtain valid
resultados, we evaluated the systems on their own terms, adjusting the KB system as necessary,
to include predecessor institutions. In WoS OE, the level at which institutional entities are
defined (p.ej., MPG as one single institutional entity), largely rules out a comparison on the
institutional level, as defined in the KB system, for some KB sectors. Además, there is no
clear documentation on the handling of structural changes over time, such as splits or
mergers. For analyses at the institutional level, this is a major limitation.
We find that WoS OE has the smallest coverage of our institution sample, en 20%, and is
mainly restricted to universities. This reflects the choice made in WoS OE not to include the
member institutes of nonuniversity research organizations. The coverage of Scopus AFID, en
the other hand, is not largely limited to one institution type, but with 85%, it is also far from
complete. These results show that the utility of the WoS and Scopus institution disambiguation
systems for bibliometric analysis is limited, as they do not currently provide full coverage of
disambiguated research organizations.
Cifra 5. Precision and recall for Scopus AFID (norte = 376).
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Comparing institutional-level bibliometric research performance indicator values
Mesa 11. Institutions with low recall for Scopus AFID
Institution name (KB system)
Rheinisch-Westfälisches Institut für
Wirtschaftsforschung e.V.
AFID and name
60029848: Rheinisch-Westfälisches Institut für
Wirtschaftsforschung Essen
Technische Hochschule Mittelhessen—THM
60000512: Technische Hochschule Mittelhessen
Fraunhofer MEVIS
60107767: Fraunhofer-Institut für Bildgestutzte
Medizin MEVIS
Hochschule Braunschweig/Wolfenbüttel, Ostfalia
Hochschule für angewandte Wissenschaften
60028838: Ostfalia Hochschule für angewandte
Wissenschaften- Hochschule Braunschweig/Wolfenbüttel
Recordar
0.03
0.07
0.07
0.10
Katholische Hochschule Nordrhein-Westfalen –
60006764: Katholische Fachhochschule Nordrhein-Westfalen
0.12
Catholic University of Applied Sciences
In the WoS OE and Scopus AFID systems, precision of the obtainable publication sets was
close to adequate levels at 0.95 y 0.96, respectivamente. Sin embargo, neither system provided high
recall rates (WoS: 0.93; Scopus: 0.86), which led to inaccurate indicator scores. Además, nosotros
find substantial variation in precision and recall across institutions, indicating that within one
sistema, these values are not systematically similar across the covered institutions but differ on
a case-by-case basis. As for the tested name search method on normalized WoS data, precisión
and recall scores are poor, so this approach does not constitute a viable alternative.
Our results show that indicator values will typically not be within tolerable error margins at
the organizational level, which we have set at ±5% of the reference value. This holds both for
size-dependent and size-independent indicators. Por eso, bibliometric indicator values at the
institutional level have only limited accuracy.
Relying on vendor disambiguation systems may incur serious inaccuracies in indicator values
at the institutional level. Therefore we conclude that for any use with policy implications,
Mesa 12. Deviation of indicator scores of Scopus AFID from KB system in Mode A (norte = 376)
Indicator
PAG
PAG(collab)
PÁGINAS(collab)
PAG(int collab)
PÁGINAS(int collab)
TCS
MCS
TNCS
MNCS
PAG(arriba 10%)
PÁGINAS(arriba 10%)
Percent deviation within ±5%
40.7
Median absolute deviation (%)
9.7
40.7
86.7
40.8
71.5
12.8
59.0
41.0
66.5
40.2
68.1
9.3
1.4
8.9
2.7
15.0
4.9
9.7
3.1
8.6
3.1
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Cifra 6. Distributions of indicator score deviations of Scopus AFID from KB system in Mode A. Diagonal lines indicate the ±5% error margin
for indicator values.
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Comparing institutional-level bibliometric research performance indicator values
additional data cleaning for disambiguating affiliation data is recommended. We stress that any
study such as the one presented in this paper shows only the current situation and that disambig-
uation systems may improve over time. The lack of adequate documentation of vendor institution
disambiguation systems, including performance figures, es, sin embargo, another barrier impeding the
adoption of these institution disambiguation systems in bibliometric studies.
EXPRESIONES DE GRATITUD
An earlier version of this paper was shared with Clarivate Analytics and Elsevier. We would
like to thank Clarivate Analytics and Elsevier for their feedback. This study was partially funded
by German Federal Ministry of Education and Research (BMBF) project 01PQ17001.
CONTRIBUCIONES DE AUTOR
Paul Donner: Conceptualización, Metodología, Investigación, Formal Analysis, Visualización,
Escritura: borrador original, Escritura: revisión & edición, Funding Acquisition. Christine Rimmert:
Conceptualización, Metodología, Investigación, Escritura: borrador original, Funding Acquisition.
Nees Jan van Eck: Metodología, Investigación, Escritura: revisión & edición, Supervisión.
CONFLICTO DE INTERESES
Paul Donner applies the KB institution disambiguation system for WoS and Scopus data in re-
search and commercial projects. Nees Jan van Eck is affiliated with the Centre for Science and
Technology Studies (CWTS) at Leiden University, which has developed its own affiliation disam-
biguation system for WoS data and which uses this system in research and commercial projects.
INFORMACIÓN DE FINANCIACIÓN
This research was supported by Federal Ministry for Education and Research, Alemania, proyecto
01PQ13001.
DISPONIBILIDAD DE DATOS
Data cannot be made available publicly due to the licensing contract terms of the original data.
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APPENDIX A: EVALUATION OF THE KB DISAMBIGUATION SYSTEM FOR GERMAN
RESEARCH INSTITUTIONS
A manual evaluation of the KB disambiguation system for German research institutions was
conducted before the main study in order to assess its basic performance parameters and to
inform any subsequent interpretations of results. The disambiguation quality is expressed in the
information retrieval evaluation metrics of precision and recall. We begin by estimating the
precision of the KB system for the data used in the study. en esta tarea, precision is the proportion
of correct document-address-combinations (assignments) to all assignments. From each result
set of assignments produced by the KB disambiguation procedure for both WoS and Scopus
datos, a random sample of 1,000 assignments was checked manually for correctness of the
mapped institution. The WoS sample contains 984 correcto, 13 incorrect and three ambiguous
assignments, leading to a precision of 0.9885 ± 0.0015. The Scopus sample contains 981
correct and 16 incorrect assignments and three ambiguous cases—leading to precision of
0.9825 ± 0.0015. We find precision to be similar for the two sets at approximately 98%.
We now consider the estimation of recall, which is more involved. Recordar, in this task, es el
proportion of correctly assigned addresses to all relevant addresses of an institution in the data.
Because the real proportion of addresses belonging to the institutions considered here is un-
conocido, it is not possible to directly calculate recall for the specific context of this analysis.
Por lo tanto, we first compute the recall for the total sets of German addresses in WoS and
Scopus for publication years from 1996 until 2013. From this basis, we will extrapolate to
the subset used in the study in a second step.
Overall recall is calculated as the number of assigned German document-address com-
binations divided by the number of all German document-address combinations. The exact
figures are stated in Table A1.
The difference between WoS (0.91) y Scopus (0.82) in recall probably arises because the
WoS addresses were processed with higher priority than the Scopus ones. Además, allá
is an issue with incomplete address records. There are instances where only the town and
country, but no institution name, are provided in an address. We found more of these cases
in Scopus than WoS, but this preliminary observation requires further examination.
Because our main study only concerns a subset of all institutions, namely higher education
institutions and nonuniversity research institutes, we are interested in an estimate of recall that
is more specific to this subset. One way to obtain such an estimate is to look into the document-
address combinations that were not successfully disambiguated and thus will not be retrieved.
More specifically, we are interested in the share of records of the selected types of institutions
among the nondisambiguated records. For this purpose, random samples of 100 direcciones
without assignments were checked manually, using both the WoS and Scopus data, to deter-
mine whether they belong to the research institutions of interest for this analysis. En el caso de
Scopus, 11 de 100 unassigned addresses belonged to institutions considered in this analysis; 86
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Table A1. Assigned vs. all document-address combinations (recordar), German addresses 1996–2013
Document-address combinations
of institutions (total set)
Todo
Assigned to German research
institutions in KB system
WoS
3,178,143
Scopus
3,530,460
2,891,537 (90.88%)
2,908,500 (82.38%)
Overall recall
0.91
0.82
addresses belonged to other institutions, with three ambiguous cases. The WoS sample con-
tained 12 addresses of institutions of interest; 84 addresses belonged to other institutions and
six cases were ambiguous. From these results, we obtain the following shares of the types of
institutions of interest, in the set of not disambiguated records, including the ambiguous cases.
WoS: 12 + 6 out of 100, a relative share of 0.18; Scopus: 11 + 3 out of 100, a relative share of
0.14. As the next step, we use these shares as factors for weighting the number of unassigned
records to obtain estimates of the total numbers of records which cannot be recalled.
Recall for the selected set can then be estimated as the number of assigned document-address
combinations in the selected set, divided by the number of all relevant document-address com-
binations in it. The unknown denominator—the total number of relevant records—is estimated
on the basis of the sample described above: number of assigned addresses in the selected set +
estimated number of addresses of interest in the set of unassigned addresses (derived from the
sample).
We illustrate this calculation for the case of the WoS. The number of assignments for the
types of institutions and publication years considered in the study is 2,211,795, which is a
subset of the 2,891,537 total WoS assignments. This is the figure for the relevant recalled
records—the numerator of recall. The number of relevant records—the denominator of recall—
is not exactly known, but is estimated based on the checked sample. Del 286,606 Alemán
address records not assigned to any institution, aproximadamente 18% belong to the types of institu-
tions considered in the study. Por lo tanto, we arrive at an estimated number of relevant records
de 2,263,384. The ratio of assigned relevant addresses to the estimated total relevant addresses
is the estimated recall value specific to the publication set of the study; en este caso, the value is
0.977.
The recall value for the Scopus data, following the same method, es 0.962, see Table A2.
Table A2. Assigned vs. all document-address-combinations (recordar), selected set
Document-address combinations of institutions
in the selected set
Todo (estimated)
Assigned
Estimated recall for
the selected set
WoS
2,211,795 + (286,606 × 0.18) =
2,263,384
Scopus
2,217,031 + (621,960 × 0.14) =
2,304,105
2,211,795
0.977
2,217,031
0.962
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