In brief, Edifix is able to find the PubMed ID (PMID) for your reference if:
(a) Edifix can successfully parse your reference,
(b) the cited reference is indexed by PubMed, and
(c) the PubMed record for the cited material contains enough corresponding data.
However, these criteria apply differently for different types of references:
BooksEven if a book reference is fully parsed and restructured by Edifix, it will usually not link to PubMed because PubMed does not index books. We say "usually" because in some cases, publishers will (incorrectly) deposit books and book chapters with PubMed as if they were journal content. Occasionally, Edifix will match your references with the record, but this is rare.
For journal references, Edifix uses “fuzzy matching” algorithms to match some or all of the authors and the article title, journal title, volume, issue, page, and date information to the corresponding PubMed record. Because journal references include more components that we can use to find a match, Edifix is more lenient with mismatching article title and author information. Some of the metadata can be missing or incorrect in the reference if the majority of the other components are exact matches with the PubMed record.
If you believe a reference should have linked to PubMed and can find the corresponding record in PubMed, please send it along to Edifix Support! We will be happy to investigate.