Expressing his personal view on the data identifier issue, Isherwood suggested that the biggest unsolved problem in music data remains the lack of authoritative, industry-wide links between songs and recordings.
He noted that many databases inside music companies hold “extensive numbers of links” between song ID codes (ISWC) and recording ID codes (ISRC).
But he said these are “generally used by such companies as a unique selling point, rather than something that might have common value and benefit.”
“If you ask most people working in operations within the music industry value chain, it is very clear that the single biggest problem that remains unsolved is having available, to everyone, authoritative links between musical works (ISWCs) and sound recordings (ISRCs),” he said.

– Music Business Worldwide