Examining Bibliometric Coverage of German Legal Journals
news
Christian Boulanger 
Christine Rimmert
In our recently published paper1, we systematically examine bibliometric coverage of German legal journals in Scopus, WoS and OpenAlex. As previous work on this topic remains scarce, we employed our combined expertise in law and bibliometrics to explore different avenues of approach, answering multiple sub questions in the process. In particular, we construct a benchmark set of journals, measure its coverage in the target databases, and further assess its quality on an item and metadata level using original publisher data. Here, we want to present a selection of our findings and key conclusions.
Key conclusions include:
- WoS and Scopus offer minimal benchmark coverage. OpenAlex, in turn, offers a substantially larger coverage (32/51 in our benchmark set), making it the most viable target database for examination.
- Trying to assess metadata quality, however, quickly shows OpenAlex’ significant limitations. Crucially, affiliation and reference/citation data are almost entirely absent, precluding meaningful citation analysis, impact assessment, or reliable institutional evaluation
- Overall, current representation of German legal knowledge production in internationally relevant bibliometric databases is poor. This renders it relatively invisible for bibliometric and scientometric analysis
Benchmark set and target coverage
To enable empirically solid observations, our first step was constructing a benchmark set of relevant law journals. Its size was to be practical yet representative, i.e. neither too small nor too large. Moreover, it did not require to be complete nor correct but just ‘good enough’ for our purposes. By trying various ways of set construction, we determined an approach centered around domain expert knowledge (in German law) to yield more suitable results then a purely classification-based one. Specifically, we utilized rankings produced by a 2009 survey among German legal scholars, aggregating it into a list 51 journals total and checking its coverage in other data sources. Concerning our target databases, we observed the following coverage (Fig.1):
Evidently, only OpenAlex contained a sufficiently large amount of benchmark set journals for promising further examination.
Assessing OpenAlex coverage quality using publisher data
To further develop bibliometrically valuable observations from our findings, we continued by examining coverage quality on article and metadata level in OpenAlex. This, however, required replacing our journal-based benchmark with an item-based one. Therefore, we requested original data of journals contained in our benchmark set directly from the respective publishers. Three publishers provided data for a total of seven journals. From this dataset, only years with available data up to and including 2023 were considered.
In terms of article coverage, trying to match DOIs found in OpenAlex and publisher data sets revealed minor discrepancies. In case of DOIs found in OpenAlex but not in the publisher data, we observed a.) temporal discrepancies, where different publication years in the two datasets (e.g. 2024 in the publisher data vs. 2023 in OpenAlex) lead to publications being excluded from our analysis because of conditions mentioned above and b.) duplicate DOIs in OpenAlex, which appeared to correspond to the same publication, but were not present in the publisher data – as was the case where a single publication had multiple DOIs. Conversely, a total of 67 DOIs were missing in OpenAlex, revealing a striking pattern: most missing articles (58/67) were from the publication year 2022, suggesting a potential issue with the timing of data updates in OpenAlex. Specifically, we observed instances where a DOI was present in a more recent OpenAlex snapshot but was missing from an earlier one.
For metadata, we focused on publication years, authors, institutions, and references/citations. Publication year discrepancies remained low and mostly confined to certain publications. Very low (OpenAlex) or non-existent (publisher) affiliation data rendered analyzing this aspect unfeasible. Looking at the number of authors for all articles, again, only certain albeit sometimes stark differences could be observed (Fig. 2). We attributed this difference mostly to missing authors of multiauthored publications in OpenAlex, author duplicates in OpenAlex, courts being listed as authors in one source but not vice versa or item titles such as ‘Autor/inn/en’, ‘Titelei/Inhaltsverzeichnis’, Buchbesprechungen’.
Trying to examine reference and citation data proved difficult as well. Publisher data was unavailable, leaving only the analysis of statistical trends within OpenAlex. For references, we could only determine 2,72 % of article items from our benchmark set in OpenAlex to contain at least one, with considerable fluctuations between journals (Fig. 3). Moreover, neither looking at internal referencing between journals in our set nor outgoing references to other items could establish insights into actual citation patterns. In addition, looking at the types of publications referenced by our set hinted most certainly at a data artifact by placing ‘ebook platforms’ at third place.
Looking the other way around, i.e. at article items in OpenAlex citing articles from our benchmark set, we could observe 18 % of the latter to have at least one citation. While this constitutes a higher amount than the above-mentioned reference percentage, it still indicates a overall poor coverage of real citation patterns (Fig. 4).
To offer at least some – albeit non-representative– approximation to a lower bound for citations, we analyzed the Scopus footprint of one journal in our benchmark set, the ‘Juristenzeitung (JZ)’. That is, we searched for its occurrence in the Scopus reference full text column using regular expressions (Fig. 5).
Notably, the results suggest a significant improvement in OpenAlex’ coverage from 2010 onwards.
Ultimately, we conducted a comparison of the Gröls/Gröls expert ranking of 2009 with a Journal Impact Factor (JIF) calculated over all available date in OpenAlex. In a completely aligned ranking, all journals could be found along the red line depicted in Figure 6. From the major deviations we observed instead, we only conclude that the available data is too limited to allow from any substantial insights.
Conclusion and Outlook
As our study shows, current representation of German legal knowledge in internationally relevant bibliometric databases within our study’s scope is poor. Only OpenAlex offers a limited but presumably growing coverage for bibliometric queries. Overall, German legal scholarship remains relatively invisible to bibliometric and scientometric analysis.
As for the reasons for this finding, we assume at least three factors at play. For one, a certain non-universality of national legal doctrinal scholarship might render it uninteresting to Anglo-American audiences primarily in the focus of the database vendors. Secondly, the peer-review model required by these databases does not correspond to publishing practices in the German legal sphere. Finally, some publishers with a large market share in the legal domain do not assign Digital Object Identifiers (DOI) to journal articles, making them much more difficult to index and therefore constituting a major impediment to bibliometric coverage.
Ultimately, we offer some recommendations to facilitate further research. Especially OpenAlex could become a source of better coverage, if new workflows in the publishing process consistently generate required metadata. Simultaneously, hard dependencies on commercially driven database vendors and publishers should be avoided in favor of decentralized and easy to access open data and tools.
Footnotes
Boulanger/Fejzo/Rimmert (2025), Law Doesn’t Count? Measuring Bibliometric Coverage of German Law Journals, Max Planck Institute for Legal History and Legal Theory Research Paper Series No. 2025-10, available as Open access: https://www.lhlt.mpg.de/4622563/2025-10?c=1879056.↩︎
Citation
BibTeX citation:
@online{boulanger2025,
author = {Boulanger, Christian and Fejzo, Daniel and Rimmert,
Christine},
title = {Examining {Bibliometric} {Coverage} of {German} {Legal}
{Journals}},
date = {2025-09-16},
url = {http://www.open-bibliometrics.de/posts/20250916-GermanLaw/},
langid = {en}
}
For attribution, please cite this work as:
Boulanger, Christian, Daniel Fejzo, and Christine Rimmert. 2025.
“Examining Bibliometric Coverage of German Legal Journals.”
September 16, 2025. http://www.open-bibliometrics.de/posts/20250916-GermanLaw/.