A Century of Migration (1830–1939): 735,000 Enriched Records from Bremen’s Ship Passenger Lists

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is a model data paper in the domain of historical/archival data drawn from primary sources. The paper provides extensive, clear, and useful historical and historiographic context for understanding the dataset. Discussion of all post-processing interventions and their results is lucid and reproducible. The result is useful and eminently reusable dataset. Minor revisions suggested.

Thorough, clear, useful historiographic and historical overview in section 2 explains the value of the dataset and contextualizes the records on which the data are based.

It would be useful to provide some brief information on the makeup and expertise of the team of people who undertook post-processing, rather than writing in the third person passive voice. For example, it would be useful to indicate whether this processing was done by a group of independent historians and without cooperation of the hosting institution/MAUS, or whether this group is a group of data curators associated with or invited by the hosting organization, etc. Using the third person passive voice, while common in academic writing, limits our understanding of who undertook different aspects of this work. How many curators were involved? Were people checking one another's work?  The expertise of data curators -- whether in data curation or data science or whether in the domain of history and migration studies -- has a bearing on our understanding of the trustworthiness of post-processing.  

I was somewhat confused by references to "family researchers", particularly before the longer description in section 4. Because the context of the archival collection was not introduced earlier, I presumed that the records were coming directly from family researchers, or in other words descendants of passengers on ships, rather than a group of volunteers transcribing collections held in an actual archive. I might suggest introducing the original collection context earlier, and referring to family researchers more specifically -- e.g., as "a team of volunteer transcribers with expertise in family history and genealogy" 

I particularly appreciated the quality and informativeness of the figures and tables provided. This is all excellent. 

Comments on the Quality of English Language

Minor typographical/grammatical errors:
-"German" should be capitalized in line 55
-Missing comma in second sentence ("The archives of Bremen—alongside Hamburg, one of Germany’s principal North Sea ports—")
-Line 348 includes extraneous text: "Nach dem sehr guten, aber auch sehr langen, historischen Exkurs"
-Is "name_here.csv" in line 356 the actual name of the referenced file, or a placeholder? 

 

Author Response

Dear Reviewer, thank you very much for taking the time to review our data paper so thoroughly and carefully. We greatly appreciate your positive feedback as well as your detailed and concrete suggestions for improvement, which have been extremely helpful in revising the manuscript.

You first noted that the paper should more clearly distinguish between the data and processing steps carried out by the MAUS and those undertaken by our own team. We have addressed this point by clarifying these distinctions in the abstract, the summary, and the data section. We deliberately chose not to use the third-person passive voice, as we aimed to maintain a consistent and coherent narrative style throughout the paper.

In this context, you also suggested that it would be useful to provide brief information on the composition and expertise of the team responsible for post-processing. We have incorporated this information at the beginning of the “Processing” section and have additionally specified that the processing was carried out by us, a group of independent historians from the University of Passau, with the consent of the hosting institution (MAUS).

Furthermore, you encouraged us to distinguish more clearly the workflow, particularly with regard to the number of people involved and their respective contributions. We now explicitly state in the paper that we—the four academic researchers from the University of Passau—consulted the holding institution, MAUS, in cases of uncertainty concerning data provenance and data structure.

We also thank you for pointing out that the introduction of the “family researchers” was ambiguous and potentially misleading. In response, we now clarify already in the summary that the data we indexed consist of original material transcribed by a group of volunteers working on collections held at the Bremen Chamber of Commerce and the State Archive from 1999 onward. This clarification has been implemented consistently at the relevant points in the manuscript and made more explicit in the abstract as well.

Finally, we have addressed all of your orthographic and editorial comments: we corrected the capitalization of “German/german” throughout the text; we inserted the missing comma in the second sentence (“The archives of Bremen—alongside Hamburg, one of Germany’s principal North Sea ports—”) in line 231; we deleted the extraneous text “Nach dem sehr guten, aber auch sehr langen, historischen Exkurs” in line 358, which was a leftover comment from our internal revision process; and we replaced the placeholder “name_here.csv” in line 363 with the actual name of the referenced file (CHUP_Passengerlists.csv).

Once again, we would like to thank you for your valuable feedback and support. We hope that our revisions adequately reflect your suggestions and have improved the clarity and quality of the data paper.

Kind regards, The Authors

Reviewer 2 Report

Comments and Suggestions for Authors

Respected Authors,

Your manuscript presents a carefully curated and extensively enriched historical migration dataset based on Bremen ship passenger lists. The work is methodologically rigorous, well- documented, and makes a substantial contribution to migration history and historical demography. The paper is well-suited to a data journal and meets high standards of transparency, reproducibility, and scholarly relevance.

Concerning Introduction and Background: The introduction provides a thorough and well-referenced overview of the historical, historiographical, and methodological context. Relevant literature is comprehensively covered, and the significance of the Bremen passenger lists is clearly established. Minor streamlining could improve focus, but the background is generally strong.

Concerning Research Design: The research design is appropriate for a data descriptor. The distinction between original and enriched data is clearly defined, and the emphasis on data preservation and traceability is methodologically sound.

Concerning Methods: The methods are described in detail and allow for reproducibility. Data cleaning, normalization, and enrichment procedures are transparent and well justified. A brief schematic summary of the workflow could further enhance clarity.

Concerning Results: Results are clearly presented through descriptive statistics, tables, and figures. The authors appropriately demonstrate the analytical potential of the dataset without overstating interpretive claims.

Concerning Conclusions: The conclusions are fully supported by the results. Limitations related to data completeness and historical bias are appropriately acknowledged, and future research applications are clearly outlined.

Concerning Figures and Tables: Figures and tables are clear, relevant, and well integrated into the text. Minor improvements to readability (e.g., font size in some figures) could be considered.

Respected Authors

Your manuscript represents an excellent contribution to the data, with significant scholarly value. Only minor editorial refinements are recommended before publication.

Author Response

Dear Reviewer, thank you very much for taking the time to review our data paper so thoroughly and carefully. We greatly appreciate your positive feedback as well as your concrete and constructive suggestions for revision.

You suggested increasing the font size in figures and tables to improve readability. We have implemented this change for three figures—those on marital status, occupational training level, and occupational sector. For these figures, the adjustment should result in a clearly improved readability. As the readability gains would have only been marginal for the remaining figures, we decided to not change them.

You also recommended providing a brief schematic summary of the workflow. We would like to note that such a schematic was already included as Figure 3 (“Flowchart of the datafication process”) directly after the abstract. However, in order to improve clarity and contextual coherence, we have now moved this figure to the end of Section 4 (“Processing”), where it more clearly summarizes the relationship between the original source material and the processed data.

Once again, we would like to thank you for your valuable feedback and support. We hope that we have addressed your comments appropriately and that the revisions have further improved the clarity and accessibility of the data paper.

Kind regards

The Authors

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

All comments addressed! Looks great. Thanks!

Reviewer 2 Report

Comments and Suggestions for Authors

Respected Authors,

I have reviewed the revised version of the manuscript and appreciate the authors’ careful and thorough response to my comments. The revision has significantly improved the manuscript in terms of clarity, methodological transparency, and documentation quality. The paper now fully meets the standards of a high-quality data descriptor.

Significance and Originality: The dataset presented in this manuscript constitutes a substantial and original contribution to historical migration research, historical demography, and the digital humanities. The large scale of the dataset, combined with systematic cleaning, normalization, enrichment, and detailed documentation, makes it a valuable and reusable research resource. The manuscript clearly demonstrates the dataset’s analytical potential and relevance for future scholarship.

Quality of Data Description and Methods: The description of the source material, data processing workflow, and enrichment procedures is now clear, detailed, and reproducible. The distinction between original and processed data is consistently maintained, and methodological decisions are well justified. The documentation of variables, classifications, and limitations is thorough and transparent, in line with best practices for data publications.

Clarity and Organization: The manuscript is well structured and clearly written. The historical background appropriately contextualizes the dataset, and the discussion of representativeness and archival gaps is balanced and precise. Tables and figures effectively support the text and enhance comprehensibility.

Adequacy of References: The references are appropriate, comprehensive, and relevant to the subject matter. The manuscript is well embedded in the existing literature on migration history and historical demography.

Respected Authors,

You have addressed all previous comments satisfactorily. I have no further substantive suggestions for improvement.