What Deserves a PID? Scalability, Scope and Granularity in Real-World PID Use Cases

As data volumes and complexity grow the question of how to scale Persistent Identifier (PID) systems becomes increasingly important. In practice, data is often organized in hierarchies - from collections to datasets to individual files - raising a key challenge: Which level of detail truly benefits users whilst keeping the systems operational? This session invites participants to share real-world use cases, challenges, and approaches to PID assignment across different domains. Depending on the context, PIDs at the collection or publication level may be sufficient for discovery and citation, while more granular identifiers are required for reproducibility, automated workflows, and machine actionability. However, increased granularity introduces overhead and complexity, potentially leading to unsustainable proliferation of identifiers. We aim to bring together diverse perspectives from different stakeholders to explore how decisions about PID granularity are made in practice, and how to balance the trade-off between too many and too few PIDs.