Music Discovery Requirements

IV.C Other Aspects of Music Discovery: Compilations

Multiple expressions are frequently issued together in a single manifestation, sometimes called an aggregate.[1] This is particularly common for recordings, which often contain expressions of more than one musical work, each of which might be by a different composer, for a different medium, of a different genre, performed by different performers, or based on different works. It also occurs with notated music, e.g. song anthologies or collections of all or some works by a single composer. Under most past and current descriptive and encoding standards, the relationships in multi-expression manifestations a) between works; and b) between works/expressions and their performers, medium of performance, or format of notated music are often recorded in notes designed for human interpretation but are not consistently linked together in a manner friendly to machine processing.

In future data creation, this problem could be solved by creating WEMI record trees and/or by utilizing linking fields (such as MARC $8, which could solve this problem but has not in reality been implemented for this purpose as yet). However, because of the lack of linking information, this problem cannot easily be solved by discovery interfaces utilizing MARC-encoded RDA and AACR2 legacy data. The Variations/FRBR project opted in favor of recall over precision and mapped data elements in a bibliographic record to all works/expressions on a manifestation, given the absence of machine-readable information indicating to which work/expression the data element applied.[2] The result is that, for example, all performers and subject headings are associated with all works/expressions contained on a compilation recording.

Recommendation: Be aware of and explore solutions to the special challenges posed by the frequency with which compilations occur for music materials, particularly that legacy data rarely links together all the attributes of the various expressions contained in a compilation in a manner friendly to machine processing.

[1]“Aggregate” may be defined as “a manifestation embodying multiple expressions,” and may represent a compilation based on specific genres or performers, or may be an apparently “random collection of expressions.” See section 5.7 of: International Federation of Library Associations and Institutions, IFLA Library Reference Model (August 2017), accessed August 25, 2017,

[2] Jenn Riley, “Leveraging the FRBR Data Model for Music Discovery and Data Sharing: Autobiographical Note,” OCLC Systems and Services 27, no. 3 (2011): 186. See also “Variations/FRBR: Variations as a testbed for the FRBR Conceptual Model. (accessed August 25, 2017).