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General

Q: How often do new articles get added to the database?

This depends on the source. We ingest from arXiv daily; from astronomy journals and other sources weekly, over the weekend; and from physics journals and other sources about once every 3 weeks, also over a weekend.

Q: How do I submit missing articles or corrections to an existing article? Missing references?

Note that these forms do not work if you’re using the basic HTML version of ADS, and occasionally, some users encounter errors when submitting these forms; email us if you run into issues.

Q: My paper is visible at the publisher but not in ADS yet.

Published articles are added to the database at regular intervals; see the publishing schedule above. In addition, for most journals, we do not add the article until it has a published volume and page number. While we appreciate the early access versions, we have found that matching them after the fact and tracking all citations correctly is difficult to do correctly.

If sufficient time has passed since the publication date and the article is still unavailable, it may be in a journal we don’t index by default. It’s also possible that the article has been added, but is not appearing the expected collection (astronomy or physics); this is generally the case if the article appears in a general science journal (Nature, Science) where we need keyword information to assign it to a specific collection. Finally, in rare cases deliveries from publishers are missing some articles. If you believe your article should be in the database already, email us for help.

Q: What are bibliographic groups (bib groups)? These appear in a left-side filter.

Bibliographic groups are hand curated by librarians and/or curators at various institutions and generally contain a list of publications produced by researchers at a given institution or using specific telescope(s). If you’re a librarian or curator interested in curating a publicly available collection, email us.

Q: My name is incorrect in an ADS record.

We receive author names and other metadata directly from the publisher. First check that your name is correct on the published article; if it isn’t, first contact the publisher directly to fix it with them. However, if your name is correct with the publisher and wrong in the ADS database, fill out this form and we’ll correct it.

Q: My name has changed since I first started publishing. How can I ensure people find all of my papers when searching for my name?

We offer three options; one or more of these may suit your needs. Email us for help deciding which option(s) are best for you and for making any necessary updates:

  • We maintain a list of author synonyms, so searches for one author name return results for both names. Let us know all of the names you’ve published under to have your names added to this list. (Note that common name variations, such as publishing under your entire first name vs. just an initial, are already included in searches.)
  • You may also consider registering for an ORCID ID and using that to maintain a personal bibliography.
  • If you’d prefer that previous names not be visible in ADS, we can modify our searchable metadata on papers published under the previous name(s) to reflect your current name. With this option, all pages within ADS (e.g. search results, paper abstract pages) will reflect the new name; note, however, that we cannot modify external data and links, such as publisher-provided PDFs.

For more information, see our name change policy.

Q: What journals and other material do you index?

Complete lists of the journals, conferences, and other sources we index may be found here.

Q: What papers do you have the full text for?

In general, we have searchable full text for most major journals in astronomy and physics, especially recent volumes. This includes articles in the arXiv.

Q: How do I get my conference proceeding in ADS?

Full instructions for submitting conference proceedings can be found here.

arXiv

Q: My arXiv paper is missing its references.

We extract references directly from the PDF for arXiv records, which doesn’t always work well, depending on reference and document format. If the paper will be published, we will get the reference list from the publisher and will update the references on the record at that point. Note also that we’re working on a new module for extracting references directly from PDFs and arXiv reference extraction should improve at that point.

Q: My arXiv paper had some citations before it was published. Will these be lost once the published version is out?

We automatically merge the arXiv and published versions of papers, including citations.

Q: The author list of the arXiv and the published versions of my paper are different. What happens when the two versions are merged?

Author metadata from the published version takes precedence, so arXiv-only coauthors will be removed from the record.

Q: The published version of my paper is out and indexed on ADS, but the arXiv version is listed separately.

The published and the arXiv versions of a paper should merge into a single entry automatically. Occasionally that doesn’t work; let us know and we’ll fix it.

Q: My name is correct on arXiv but wrong in ADS. How can I fix it?

Submit your corrections using this form.

Q: My name is wrong in arXiv, will you fix it?

You’ll need to contact the arXiv directly for corrections to your papers on their site.

Refereed status

Q: Why is my PhD thesis listed as refereed?

ADS has decided to list PhD theses as refereed because they go under the review of a thesis committee and are thus “peer reviewed.” However, if you prefer to not see PhD theses appear in your search results, restrict your search results to articles only using the “Publication Type” filter in the left-side column.

Q: A conference proceeding is listed as non-refereed even though it underwent peer review.

Most conference proceedings are not refereed. They may be reviewed by an editor, but rarely is there the kind of rigorous review as is done by many journals. (In general, users and editors and librarians and publishers all have different opinions on what constitutes “peer-reviewed.”)

If a publication or a conference is generally not peer-reviewed, all articles/proceedings within that publication/conference will automatically be listed as non-refereed. If a particular article/proceeding within the generally non-refereed publication/conference is peer-reviewed, have the editors email us to confirm and we can correct the listing.

Submissions

Q: How do I submit my PhD thesis?

Some institutions send us their recent PhD theses directly, though it may take a few months post-defense for us to receive them. However, if your institution does not send us your thesis, you have several options to add it to our database:

  • Zenodo Astronomy Thesis collection: This is an open-source repository of astronomy theses and dissertations which is automatically ingested into ADS roughly once a month. If your thesis is already indexed by ADS but the text is not openly accessible, you can upload a copy of the PDF to make it openly available. This is a good option if you’d like your thesis to be openly available and it’s not currently accessible online.
  • ADS submission: You can submit your thesis metadata directly to ADS for indexing. If you want the PDF to be linked to the record, it will first need to be hosted somewhere online and then you can provide the URL and other metadata using this form. If the text of your thesis is not already available online and you’d like it to be, consider submitting it to the Zenodo collection.
Q: My name (or title, etc.) is misspelled on my paper.

If it is wrong on the publisher’s website, you’ll need to contact them to correct the error, as we’ve agreed with the publishers to reflect the data they pass on to us.

If it’s right on the publisher’s website but wrong on ours, we’re sorry for the error! Contact us so we can fix it.

Q: How can I get my software package indexed in ADS?

Software records are automatically indexed in ADS once they have a Zenodo record and have been cited at least once. If you’d like to make your software records eligible for indexing in ADS, complete the following steps:

  1. Upload your software code to Zenodo. You can do this directly or by linking to a Github repository. If you link to a Github repository, you can specify a specific release or version, or you can link to the top-level repository to create a non-version-specific record.
  2. Get the BibTeX (or other bibliographic format) record from Zenodo and cite it in your paper as normal. Your software will not yet be in ADS, so make sure to get the citation information from Zenodo.
  3. Once your paper has been published and is indexed in ADS, ADS will recognize that the bibliography contains a software record and will automatically create a corresponding software record in the ADS database. The publisher will be listed as Zenodo and the bibstem (the abbreviation that appears in the bibcode) will be zndo. The publication type for these records is software.

Some things to keep in mind:

  • Zenodo allows you to create different records for different versions of your software, which generally correspond to different releases in Github. This can be beneficial if the software has changed substantially with time, or if different authors have worked on different versions of the code and need to be acknowledged as appropriate. ADS will index each Zenodo version of your software separately, as long as each has citations. Currently, citations are counted for each version separately, but eventually it will be possible to see all citations for all versions of a software package in one record in ADS.
  • The Astrophysics Source Code Library indexes astronomy-related software that has been used in a publication. ADS indexes these ASCL records (bibstem: ascl, publication type: software) and they can collect citations similarly to the process above. One difference between the two processes is that ASCL indexes only the non-version-specific record while Zenodo indexes each version separately. It is possible for a given software package to be in both Zenodo and ASCL, if they fit the necessary criteria for each.
Q: I submitted some ORCID claims but they don’t show up when I search by my ORCID ID.

These can take up to 24 hours to index. Please contact us if they aren’t showing up after this time.

This section is intended to be a guideline for editors and authors wishing to submit conference proceedings for inclusion in the ADS Abstract and Scanned Literature Services. Any questions about the procedure should be directed to adshelp@cfa.harvard.edu.

The ADS is pleased to include any conference proceedings volume, as well as individual conference proceedings abstracts. This includes both electronic and printed conference proceedings. We have a set of naming conventions detailed below, but are flexible if there is a different naming scheme which is more appropriate for your particular conference. If you would like to have your conference proceedings included in our database before your conference, we request that you submit them to us one month in advance of the start of your conference.

Submitting Bibliographic Records for the ADS Abstract Service

Please send us an email at adshelp@cfa.harvard.edu with the information to make a conference entry in the ADS.

In addition a file containing the following should be sent to the ADS. Individual Article Entries should include the following tags ( ( * ) items are required.)

( * ) %T Title
( * ) %A Author List
%F Author Affiliation
( * ) %P First Page of Article
%L Last Page of Article
%I Links to online resources (see below)
%B Abstract Text
%Z References
%K Keywords

Please note that there are many more details that you can add but these are the required minimum tags. A complete list of ADS tagged fields can be found here. Please note that references containing TeX/LaTeX formatting, AASTeX macros and HTML entities are acceptable.

A long entry should continue on the next line(s) with no repetition of the percent sign and keying letter. All entries should be in ascii and there should be no tabs or control characters. Blank lines can delimit paragraphs in the abstract, but should not otherwise be present within a record. A title, author list, and page number are required. Other information such as author affiliation, links to online full-text, abstract text and references are strongly recommended as well. The more information that you can provide for each article, the better. This additional information will aid in searching and using advanced features in the ADS.

This information can be submitted via email to ads@cfa.harvard.edu or placed on our anonymous ftp site, under ftp://adsftp.harvard.edu/pub/Conf. Please send us an email indicating when you have transferred things to us, so that we can include it in our database as soon as possible.

Including Full-text Papers in the ADS

It is possible for us to make the full-text of articles published in conference proceedings available via the ADS Article Service. This section describes the requirements and procedures to be followed in order to do that.

Note: We do not publish original material that is not published elsewhere, since we are not a publisher.

Provide written permission from the copyright holder allowing the ADS to publish electronically the papers in the conference proceedings. The relevant letter should state something along the following lines:

The <full description of the copyright holder> grants permission to the NASA Astrophysics Data System at the Smithsonian Astrophysical Observatory to:

1. Convert postscript files to tiff files for <name of conference>

2. Add a note at the bottom of each page with the following content:

    (©) <name of copyright holder> - Provided by the NASA Astrophysics Data System

3. Make the images of the articles electronically available, free of charge, for all volumes starting 1 year after publication

Feel free to modify as you see fit, especially item three, then send a copy of a signed copy of the permission letter to:

    Donna Thompson
    NASA Astrophysics Data System
    Harvard-Smithsonian Center for Astrophysics
    60 Garden Street, M.S. 83
    Cambridge, MA 02138
    USA

Send us either a printed copy of the conference proceedings book or (if available) the set of full-text files used to create the proceedings. If only a printed book is available, please send it to Alberto Accomazzi at the address listed above along with the permission letter. If full-text PostScript or PDF files are available for all papers, please read on.

To submit the full-text files with the necessary information for us to process them, you will need to create a tar or zip archive and transfer it to our ftp server. This is what must be included in the archive file:

  • All the files containing the full-text, including front-matter (introductory) and back-matter (index) pages if available. You should make sure that these files are either in PostScript or PDF format, and that they have been created using 600dpi or higher resolution fonts. (Note: if you are using dvips to create the postscript file, you can specify the options -D600 -Z on the command-line to have 600dpi fonts included).

  • A file named README, containing general information concerning this publication, the name and email address of the person submitting the full-text papers to us, and any additional information we should be aware of.

  • A file named PUBLICATION, containing the full name of the conference or book (you should use the same name given in the journal field above).

  • A file named COPYRIGHT, containing the copyright string that needs to be displayed at the bottom of each page that the ADS creates and places online in its article service (please do not try to include the copyright symbol © since we already do this for you).

  • A file named BIBSTEM, containing the bibliographic abbreviation for the publication (e.g. ASPC..117 or 2000immm.proc). This should be the same abbreviation that has been used to create the bibliographic entries described above.

  • Optionally, a PAGEMAP file containing mapping of full-text file names to page numbers, if these cannot be determined from the full-text files themselves. Whether or not this is needed is a function of how the files were originally created; usually if you used LaTeX and dvips to create the postscript files then the page numbering displayed on each page is carried into the postscript files and can be automatically extracted at least for “regular” pages. Pages which are part of the front-matter may need to have entries associated with them. The format of the PAGEMAP file is the following:

          # This is a comment
          file1.ps    C1-C4         # first file has cover pages 1-4
          file2.ps    C6            # second file has cover page 6
          file3.ps    1-8 8A 9-15   # third file has pages 1-8, insert 8A, 9-15
          file4.pdf   16-           # fourth file has pages 16 and up
    

When in doubt, please contact us for help.

Create a compressed tar or zip archive containing of all the full-text files, the README file, and name of the file using (if possible) the standard acronym adopted by the ADS in naming bibliographic entries for the conference. For example, the archive file containing papers submitted to the ASP Conference Proceedings n.117 should be named ASPC117.tar.gz or ASPC..117.tar.gz. The archive for files containing the conference 2000immm.proc should be named 2000immm.proc.tar.gz.

Deposit the tar archive on our anonymous ftp server under the URL ftp://adsftp.harvard.edu/pub/Conf and notify us. We will contact you with any questions regarding the full-text processing of the files.

Archiving Conference Proceedings in the ADS

As more conferences are published electronically, editors are turning to the ADS for long-term archiving of their full text proceedings. We can agree to this under the following conditions:

  • The conference is originally published elswhere (e.g. through a university or observatory publication, or through another publisher).
  • We receive the pdf or postscript files as described above.
  • The data have been published at least three years ago.

The ADS Tagged Format

We welcome the submission of Bibliographic Records from librarians and researchers willing to provide this information to the ADS. To facilitate the insertion of this data into our databases, we request that the records be submitted in electronic form and adhere to the following format:

%R Bibliographic Code (required)
%A Author List
%a Review Authors
%b Book Authors
%F Author Affiliation
%J Journal Name
%D Publication Date
%P First Page of Article
%L Last Page of Article
%T Title (required)
%t Original Language Title
%C Abstract Copyright
%O Object Name
%G Origin
%I Links to other information
%U Unified Astronomy Thesaurus (UAT) keywords
%K Keywords
%M Language (if not English)
%X Comment
%W Collection (if submitting for more than one)
%B Abstract Text
%Z References

A long entry should continue on the next line(s) with no repetition of the percent sign and keying letter. All entries should be in ascii and there should be no tabs or control characters. Blank lines can delimit paragraphs in the abstract, but should not otherwise be present within a record. The bibliographic code is the only field which is required for all records, but author list, journal name, publication date, and title are strongly recommended as well. Additional records should be separated by a blank line.

Fields in the Tagged Format

Detailed descriptions of each field follow.

Bibliographic Code

The bibliographic code is a 19 digit code (see Bibcodes)

Author List

The author list should contain semi-colon separated authors listed with last name first, followed by first name or initials. A paper with one author would be listed as Minkowski, R. A paper with multiple authors would be listed as

Neubauer, F. J.; Burwell, C. G.; Miller, W. C.

Authors whose names contain “Jr” or “III” should be entered as

Roberts, L. C., Jr.

Review Authors

This contains the review authors in the same format as the regular authors.

Book Authors

This contains the book authors in the same format as the regular authors.

Author Affiliation

The institution with which the author is affiliated. If more than one author affiliation is to be listed, here is the suggested format:

AA(first author's institution) AB(second author's institution) ...

Email addresses can be specified in the author affiliations. Please mark them as follows:

<EMAIL>email address</EMAIL>

Journal Name

This entry contains the reference information, including the journal name, volume, and page range. Also include here any editors of books or conference proceedings.

Publication Date

This contains the publication month and year of the article in the format MM/YYYY (i.e. 02/1995). If no publication month is known, please use a month of 00.

First Page of Article

This contains the first page number of the article.

Last Page of Article

This contains the last page number of the article.

Title

%T contains the title of the article. If there is also an original language title, it can be submitted with a %t and the language included in the %M tag.

Object Name

This contains the name of Objects described in the paper. These are normally handled through SIMBAD and are therefore not part of the user input except in special circumstances.

Origin of the Article in ADS

This contains the source of the record in ADS.

This contains a copyright statement of the abstract, such as (C) 1990: American Astromomical Society

Unified Astronomy Thesaurus keywords

This contains keywords from the Unified Astronomy Thesaurus (UAT), separated by a comma.

Links should be preceded by their link type and semi-colon separated, e.g.

%I DOI: 10.1234/article_doi; PDF: https://article_pdf

Available links include arxiv, data, doi, electr, pdf and other.

Keywords

This contains keywords related to the article, separated by a comma.

Language

This contains the original language of the article.

Comment

This contains author comments.

Collection

This contains the database key if you are submitting abstracts for multiple databases (astronomy: AST, physics: PHY, general: GEN).

Abstract

This contains the abstract text. Any line beginning with at least one blank space will be assumed to be a new paragraph. New paragraphs may also be delimited with blank lines. Abstracts should not contain tables, and will appear best in the system if they contain only ascii characters.

References

This field should contain the list of references cited by the current paper. They should be formatted so that there is just one reference per line, e.g.:

%Z Bechtold,~J., \etal 1994, \aj, 108, 374
   Massa, D. L., & Savage, B. D. 1984, ApJ, 279, 310
   Savage, B. D., & Mathis, J. S. 1979, ARA&A, 17, 73

Please note that references containing TeX/LaTeX formatting, AASTeX macros and HTML entities are acceptable.

Examples of Records in Tagged Format

This section shows a few examples of our tagged format.

Example 1:

%R 1993ApJ...415...50C
%A Cavaliere, A.; Colafrancesco, S.; Menci, N.
%J Astrophysical Journal, Part 1, vol.415, no. 1, p. 50-57.
%D 09/1993
%L 57
%T Distant clusters of galaxies detected by X-rays
%K Cosmic Plasma, Dark Matter, Galactic Clusters, X-ray Astronomy, Baryons, Luminosity, Redshift
%B The dynamical masses of groups and clusters of galaxies decrease on average with increasing redshift, after the hierarchical cosmogonies dominated by direct collapses of dark matter overdensities. We show that the masses of intracluster plasma emitting in the X-ray band are to decrease more rapidly. We also show that consideration of the intrinsic spread in the dynamical formation times leads us to predict more numerous faint sources at given dynamical mass. The model we compute yields steeper luminosity functions in the X-ray band with a specific change in lookback time: the bright end shifts back. Such negative evolution is fast even at modest redshifts z less than about 0.5 if the external gas infalling into groups of clusters was preheated and has cooled down after z of about 1.5-2. If so, the evolution is considerably faster in the X-ray than in the optical band, comparing interestingly with data from the existing surveys.
%Z Abell, Ci. 0. 1958, ApJS, 3, 211
Barcons, X., Fabian, A. C., & Rees, M. J. 1991, Nature, 350, 685
Bardeen, J. M., Bond, J. R., Kaiser, N., & Szalay, A. 5. 1986, ApJ, 403, 15
Blumenthal, Ci., Faber, S. M., Primack, J. R., & Rees, M. J. 1984, Nature, 311, 517
Bohringer, H., et al. 1991, in Proc. NATO ASI "Clusters and Superclusters of Galaxies," ed. A. C. Fabian (Dordrecht: Kluwer), 71 
Burg, R., Cavaliere, A., & Menci, N. 1993, ApJ, 404, L55
Cavaliere, A., Gursky, H., & Tucker, W. H. 1971, Nature, 231, 437
Cavaliere, A., & Colafrancesco, 5. 1988, ApJ, 331, 660
---. 1990, in Clusters of Galaxies (Cambridge: Cambridge Univ. Press), 43
Cavaliere, A., Burg, R., & Giacconi, R. 1991, ApJ, 366, L61

Example 2:

%T Adsorption behavior of a textile dye of Reactive Blue 19 from aqueous solutions onto modified bentonite   
%A Gök, Özer; Safa Özcan, A.;Özcan, Adnan
%P 5439

Example 3:

%T Seeing Red: Extremely Red Objects from the Cadis K' Survey
%A Thompson, D.; Beckwith, S. V. W.
%F AA(Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg, Germany)
%P 13
%B We discuss various interpretations of the nature of extremely red objects (EROs), discovered in the first of 7 deep, wide-field K' images in the CADIS survey. Point sources with K' = 20.5 mag are detected at the 5 sigma level over an area of 125 arcmin^2. A total of 20 EROs meeting the selection criteria (R-K') >= 6^{m} and K' <= 19.75 mag were selected from the data, giving a surface density of 0.16 +/- 0.04 arcmin^{-2} for all EROs and 0.016 +/- 0.011 arcmin^{-2} for bright (K' < 19^{m}) EROs.} 

Example 4:

%T Chandra observations of M31 and their implications for its ISM
%A Primini, F., Garcia, M., Murray, S., Forman, W., Jones, C., and McClintock, J.
%F AA(Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), AB(Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), AC(Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), AD(Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), AE(Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), AF(Harvard-Smithsonian Center for Astrophysics, Cambridge, USA) 
%B We have been regularly observing the bulge and inner disk of M31 for nearly one year, using both the HRC-I and ACIS-I instruments on the Chandra X-Ray Observatory. We present results from our program that are of interest to the study of the ISM in M31. In particular, we find that the unresolved emission within 3' of the center of M31 has a distinctly softer spectrum than that of most of the resolved X-ray sources in the region. Preliminary spectral analysis of bright point sources in the bulge shows no evidence (within the poor statistics) for soft spectral components, but does reveal significant extra-galactic X-ray extinction (NH ~ 1021 cm-2). We find no new X-ray counterparts to supernova remnants to date. 

Example 5:

%T We Do Not Forget Johannes Kepler
%A Wszołek, B
%B Year 2009 was announced as the International Year of Astronomy. This was to mark 400th anniversary of the first astronomical observation through a telescope by Galileo. From the other hand, this year marks 400th anniversary of Astronomia Nova, the famous work of Kepler published in Prague in 1609. Two laws of planetary motions opened human efforts to understand gravitational force; so the overall cosmic space conquest, with its great importance not only for astronomy, was developed thankful to Kepler's work. This contribution is thought to show the most inspiring ideas of Johannes Kepler, published in Astronomia Nova and in other his books. 
%I PDF: FILE:proc16_02.pdf

How do you evaluate journals for inclusion?

The ADS evaluates all journals for coverage using the criteria listed below. We seek comprehensive, but not all-inclusive, coverage of the field of astronomy, and we take into consideration relevancy of content, standards of presentation, and regularity of publication. We evaluate journals on an ongoing basis and add or delete journals regularly. ADS reserves the right to exclude content deemed inappropriate for its collection or inconsistent with its editorial policies. To be accepted for coverage, a journal must:

  • Be relevant to astronomy
  • Be of a quality and scope of interest to an international audience
  • Have an ISSN
  • Be registered with CrossRef
  • Follow standard conventions for scholarly journals
  • Have an informative title and descriptive article titles
  • Include full addresses for authors
  • Include abstracts and key words
  • Include references that are current, from quality journals, and of an appropriate number for the article in a standard format
  • Contain usable metadata including: abstracts, titles, and keywords
  • Demonstrate diversity of reviewers and authors
  • Include all or mostly all original articles
  • Contain articles that are substantiated with empirical data or other means
  • Be published on a regular schedule appropriate for the established frequency of the journal
  • Have articles that are written by professionals in their field.

In addition, e-journals must:

  • Provide evidence of archiving arrangements, online or otherwise
  • Include a posting date for articles and revisions
  • Have published at least three issues

Features that support acceptance:

  • Sponsorship by a astronomy or physics association or other society
  • Astronomers or physicists among editorial board members and authors
  • Indexed in other scholarly databases
  • Online access
  • English table of contents
  • Transliterated references
  • Frequency of publication clearly advertised on masthead or web page

For e-journals

  • Presence of version number
  • Indication of where previous versions can be obtained Links

Relevance: An article that includes any of the following may be relevant:

  • the scientific study of astronomy
  • content in any of the subfields of astronomy or physics
  • non-astronomy content of interest to astronomers in different subfields
  • content in related fields that has astronomical relevance

If you have a journal to be evaluated, please feel free to send email to us at adshelp@cfa.harvard.edu.

The ADS curation model is represented by the diagram below (see Kurtz et al. 2021).

ADS Curation Model
ADS's tiered curation model. The core collection represents disciplines where its curation is strongest and its coverage is authoritative. The surrounding tiers are connected to the core via the citation network.


The Core Collection consists of the main journals for the disciplines covered, the most influential journals. As we move into the inner and outer rings, curation efforts decrease. A qualitative characterization of the model is given below.

Core: main journals for discipline

  • Complete, authoritative coverage of the literature
  • High-level data products and software indexed
  • Links to datasets and archives
  • Most refereed journals covered
  • Some conf proceedings, some gray literature
  • Citation and fulltext coverage incomplete

Outer Ring: connected to inner content

  • Incomplete coverage of the literature because outside of disciplinary scope
  • Includes content from multidisciplinary journals (e.g. Nature) or repositories (arXiv)
  • No curation applied other than basic error corrections

How do we determine which journals go in which section? Once the Core Collection has been populated, appropriate journals for the Inner and Outer Rings can be determined as indicated in the diagram above. Up to now, journal selection for the Core Collection has been heuristic, based on qualitative arguments and domain knowledge. We felt it was important to formulate selection criteria based on quantitative arguments. These quantitative selection criteria are unavoidably based on journal metrics and just like any metric, journal metrics are not without controversy. We have settled on the so-called Journal Eigenfactor as the main indicator for journal importance. More details on how this metric was used to determine the journal selection for the Core Collection can be found in this blog.

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