A slightly revised version (v. 1.41) of the MLA Best Practices for Using LCMPT (March 31, 2020) is now available, and should be used in place of the previous version.
The main change is the deletion in its entirety of footnote 10 in version 1.4. Deleted:
As of this writing, 382 subfields $e, $r and $t are defined in the MARC Authorities Format, but are not yet approved for use in LC/NACO authority records; see the Descriptive Cataloging Manual, Section Z1 for more information (via Cataloger’s Desktop or https://www.loc.gov/catdir/cpso/dcmz1.pdf). Aside from that restriction and the second indicator difference mentioned above, these best practices guidelines apply equally to 382 fields in bibliographic and authority records.
This brings the document in line with the change by LC, announced in March ahead of the April, 2020 update to DCM Z1, that subfields in the 382 field (Medium of Performance) are available for use in authority records (by NACO-Music Project participants).
$e (Number of ensembles of the same type)
$r (Total number of individuals performing alongside ensembles)
$t (Total number of ensembles)
Additionally in v. 1.41, the quoted scope notes for “band” and “wind ensemble” have been updated to match the revised notes to authority records for each of those terms. There is also an example showing subfield $r with an accompanist that was inadvertently omitted from 1.4.
Please make sure your bookmark points to the appropriate Best Practices landing page (not a PDF) on the CMC website to ensure you are linking to the current version. For LCMPT, that is: http://cmc.blog.musiclibraryassoc.org/documents/best-practices-for-using-lcmpt/. (Similarly, please bookmark the landing page of the LCGFT BPs.) Older versions are archived on the site for reference. As always, your feedback is welcome via the suggestion box.