Ovid Communications
Database Reloads

Ovid MEDLINE Update

Dear Ovid MEDLINE Customer:


On 29 September, the NLM supplied us with an unexpected and unusually large set of replacements, containing 1.62 million records. These replacements are a mix of corrections to fully indexed status MEDLINE records (200,000), and replacements for MEDLINE In-Process/Non-Indexed records (1.4 million).

As we start to implement this huge update over the next weeks, we want to inform you, as it may affect some saved searches, and AutoAlert result counts for Ovid MEDLINE.

We expect the volume of In-Process records (database segment prem) to increase by a factor of 5 daily over the next weeks, and on 14 October we expect to load a large set of corrections (database segment medc).


Why did the NLM create such a large update?
Upon our request the PubMed Helpdesk provided the following explanation to Ovid: we apologize for the unusually high number of modified citations in PubMed. NLM Serials staff updated the ISO abbreviation for a number of journals and that process also modified the PubMed citations.


What exactly changed?
For all 1.62 million records, the “ISO Journal Abbreviation” (IO) field was updated to reflect the new Journal Abbreviation.
ISO Journal Abbreviations in PubMed/MEDLINE follow the international ISO 4 standard, a uniform system for the abbreviation of serial publication titles. Where needed, the NLM also changed the PubMed TA Title Abbreviation field. On Ovid this is called the Journal Abbreviation field (JA).


What does this mean for Ovid MEDLINE users?
We expect the impact for most Ovid users to be minimal, but we do recognize the following situations:

  1. If existing search strategies contain searches that include the IO or the JA field, they may retrieve different results after the updates are implemented. Please note that regular keyword searches (.mp) on Ovid do not include the Abbreviation fields, and are not affected.
  2. All status “In-Process”, “In Data Review” and “PubMed-Not-MEDLINE” records that are replaced will be alerted on. If your AutoAlert does not have “History deduplication” enabled, the updated records will be seen as new records, which may cause a significant increase in AutoAlert results.
  3. AutoAlerts that include the Ovid MEDLINE Revisions segment (medc) will not be affected. While we normally do alert on all Status MEDLINE corrections in the monthly updated Revisions segment, we will plan NOT to alert on MEDLINE corrections supplied in the set of 1.62 million replacement records. By doing so we will prevent large spikes in AutoAlerts that include the “medc” segment.


Feel free to contact Customer Support with any questions by sending an email to [email protected].



Wolters Kluwer – Ovid

Tags: MEDLINE,Ovid,