EBSCO Discovery Service (EDS) is a ‘discovery layer’- an interface for searching and accessing proprietary EBSCO records and content, as well as records and content coming from and/or residing in other vendor and publisher platforms.  It is not exactly a ‘database’ per se; it’s more accurate to think of it as a searchable collection of selected databases.  Those databases contain metadata records - some of which (the ones with 'HTML full text') contain the actual content, while others allow for the attachment of links to the full-text (or streaming video or audio) content, while others do neither, and should receive an ILL link if the record is for a print resource. 

In the records that do have links to content, those links are either internal to EBSCO – i.e. they link to content purchased by EBSCO and residing (in some cases, partly) on EBSCO servers – or they link to content external to EBSCO – i.e. content that is only on a vendor/publisher platform such as JSTOR or NAXOS.

Databases internal to EBSCO

Complementary Index (Formerly known as the Publisher-Provided Full-Text (PPFT) Searching File) 
This represents full text supplied by primary publishers for searching (but will not display without a subscription) in EDS. It does not include full text for searching from all publisher content - only that which is not contained in other content providers’ data sets or via full-text databases.  Publishers included in this data set include Elsevier, Wiley, Springer, Taylor & Francis, Sage, Nature Publishing, IEEE, ACM, Oxford, Cambridge, and thousands of others. The file includes journals, books, proceedings, and more.  NOTE: In practice, what this means is that with some major publisher content (such as Elsevier/Science Direct), often the user gets an external link to content, even if that publisher’s content is technically considered part of the Complementary Index.  In those cases, the line between an ‘internal’ EBSCO database and an ‘external’, i.e. ‘EBSCO Partner’ database gets very blurry.

Academic Search Index
The Academic Search Index is included both for customers who subscribe to an Academic Search product such as Academic Search Ultimate (which UMBC does currently subscribe to) and thus have full-text access to most of its contents, and also for EDS Customers who might not have subscribed to an Academic Search product.

Business Source Index
Same as the above with the Academic Search Index, except for the Business Source product line.

Supplemental Index
This includes EBSCO-enhanced metadata for journals and  magazines (including peer-reviewed journals) NOT found in Academic Search or Business Source, as well as books, newspapers, and more. This is NOT metadata from subject indexes which need a subscription to be included in EDS.

Discovery eBooks/Ebook Index 
Discovery eBooks provides metadata and searchable full text for eBooks purchased directly from primary publishers such as Wiley, Sage, Cambridge University Press, and Oxford University Press. Metadata from discovery eBooks is available for all EDS subscribers. Full text is available for those customers who purchase books from any of those publishers. Content subscribed via EBSCO eBooks should be fully available in EDS.

Subject (Ebscohost) Indexes (Resources Available via ‘Platform Blending’).
EDS includes databases that do not work directly with discovery services,  such as: America: History & Life, Art Abstracts, ATLA Religion Database, Biological Abstracts, CAB Abstracts, CINAHL, EconLit, APA PsycINFO, RILM Abstracts of Music Literature and so forth.  As long the subscription is via Ebscohost (which it is for UMBC, as it is for most institutions), these subject indexes can be included in EDS searches.  Note: linking to content is usually a two-step process where the link in EDS takes the user to a secondary record (which usually contains a link to content, but not always) in an Ebscohost database.  Sometimes, the link can even take the user to an external/non-EBSCO platform.

Databases external to EBSCO

• EBSCO Partner Databases 
  EBSCO Partner Database are databases for which EBSCO has permission to provide metadata to customers regardless of whether they have subscriptions*. Examples include JSTOR,  LexisNexis, DOAJ, etc.  This is a large and ever-growing list, but it is important to note that it doesn’t, and probably will never, include 100% of any library’s subscribed or purchased content, even when combined with the content represented in the internal EBSCO databases.  Also, linking to this content tends to be more problematic than linking to content from internal EBSCO databases such as the Complementary Index or Academic Search Index.

* A small percentage of Partner Databases are for mutual customers only. That is, if you have a subscription, records (and usually links to content) can be added to your version of EDS, but if you don’t have a subscription, it cannot be included.  Examples include AP Image Collection, ArchiveGrid, ARTstor, and Web of Science.