A persistent identifier (PID) consists of a unique string of alphanumeric characters and serves as a reference link to a particular individual, object, or entity. The U.S. Department of Energy has provided a good definition of it:
A PID is a digital identifier that is globally unique, persistent, machine resolvable, has an associated metadata schema, identifies an entity, and is frequently used to disambiguate between entities.
A study by Pew Research Center states that "38% of webpages that existed in 2013 are no longer accessible a decade later." A PID is recorded with an international registry and is maintained on an ongoing basis to ensure that it remains valid as a reference link over time. As such, it prevents the link rot problem and is widely adopted in the scholarly communication ecosystem to enable readers and researchers to find the referenced individual, object, or entity. Common PIDs in scholarly communication include:
In addition to functioning as a stable reference link, each PID is associated with an online record that holds a variety of descriptive information about the referenced individual, object, or entity. Thus, it prevents ambiguity or confusion and is especially useful in reporting and identifying connections. The image below illustrates how PIDs optimize scholarly communication in the research lifecycle. The video at the bottom provides further information about PIDs.
This guide aims to provide an introduction to PIDs commonly used in scholarly communication. If you have any questions, feel free to contact the Center for Digital Scholarship.
"The PID-Optimised Research Lifecycle" by Josh Brown, Phill Jones, Alice Meadows, and Fiona Murphy is licensed under the Creative Commons Attribution 4.0 International License.