From the NLM Cataloging Section:
NLM is sharing with the community some of the local documentation used by NLM catalogers when creating RDA records.
In general, as a member of the Program for Cooperative Cataloging (PCC), NLM is following the BIBCO and CONSER guidelines developed for RDA.
The NLM Metadata Application Profile (MAP) is based on the MAPs developed by the Library of Congress and the PCC as a quick reference tool for catalogers and provides guidance on recording all RDA elements considered to be “core” by NLM. There is a great deal of similarity between the PCC RDA BIBCO Standard Record (BSR) Metadata Application Profile and the NLM Metadata Application Profile.
However, the NLM MAP includes instructions for serials as well as monographs and also records some local practices that may be unique to NLM. The MAP is intended to be used in conjunction with the document MARC 21 Coding to Accommodate RDA Elements while we are still working in a MARC environment.