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Updated Information as of January 6, 2026

Patron Driven Acquisition (PDA) and Demand-Driven Acquisition (DDA) : Records from vendors are uploaded into our system and made available for patron discovery, but remain unpurchased until a patron requests that CUL acquires the title. Then the title is 'purchased'.

As all the unpurchased titles are availabe in the catalog, title counts will include them, and we need to exclude them unless they have been purchased. For CUL, the purchase status is available in the MARC record in the 899 field, subfield 'a' . 

If the 899(a) field contains the following codes, it indicates an unpurchased ebook title (the vendor for PDA and DDA e-books is Casalini, Ebsco, and Jstor): 

1. PDA_casaliniebkmu : this is an unpurchased e-book from Casalini (changed to CUL_casaliniebksmu once purchased)
2. DDA_jstorebksmu
3. DDA_ebscohostebks 

• Once a title is purchased, the 'PDA' in the code is changed to 'CUL', so that PDA_casaliniebkmu will be changed to CUL_casaliniebksmu once purchased. 
• Even though we no longer have a contract for DDA with ProQuest, we still have titles with CUL_pqecebks in our catalog as they have already been purchased. 
• As of the date of this update, there is no contract as yet for on-demand print books.
• Note that we used to have a PDA contract with Proquest Coutts, but this has been discontinued and all the titles from that vendor have been supressed. 

(Information above from Natalya Pikulik (Library Technical Services; np55) and confirmed by You Lee Chun (Library Technical Services Acquisition; yc395). Peter McCracken (Interim Director, Acquisitions and E-Resource Licensing Services; phm64) copied on emails.

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June 2024

For quite some time, CUL has been removing counts of its unpurchased PDA/DDA (Patron Driven Acquisition/Demand Driven Acquisition) titles for its annual data collection as requested by national definitions. These can be for physical or electronic titles, including media if any. However, CUL decided that it would not remove EBA (Evidence Based Acquisition) titles, as that model is based in part on subscription plans, and CUL does not remove e-resources purchased on a subscription basis, vs. on a permanent basis. (LTS’s Jesse K. and Weill’s Michael Wood agree on including EBA counts, and ACRL has since condoned it through its FAQs.) At least once a year, A&P consults with LTS staff to see which coding should be used to remove these counts.

...

AND sm.CONTENT ILIKE ANY (ARRAY['DDA_pqecebks', 'PDA_casaliniebkmu'])

One Here's one example of an unpurchased item title in the catalog (a matching instance record 856 field provides access info; consult with technical services staff for more information):

Links of interest from LTS:

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• Any records with 899 code starting EBA_* are not perpetual access.
• Any records with 899 code starting CUL_EBA* are perpetual access.
• But note that some records for EBA don’t have 899 code at all, as they are EBSCO records. See: https://confluence.cornell.edu/x/gSuZGQ

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