Metadata Basics

This metadata guide provides a starting point for anyone interested in understanding metadata, especially those conducting or supporting research activities. 

Note about guide updates: This guide was originally published in 2017, and a lot has changed since then. While most of the information here remains relevant, guide review and updates to provide more recent and comprehensive coverage are underway in 2024.  

Metadata is commonly described as "data about data." While easy to remember, this definition is far too vague to be useful. The definitions below provide better explanations in plain English. 

Definition from the National Information Standards Organization (NISO)
"Metadata is structured information that describes, explains, locates, or otherwise makes it easier to retrieve, use, or manage an information resource." 

Definition from Steven Miller, Information and Metadata Lecturer
“Extra baggage associated with any resource that enables a real or potential user to find that resource and to determine value…”

Definition from Karen Coyle, Digital Librarian and Author of Coyle's InFormation
“Metadata is constructed, constructive, and actionable.”

• Constructed - a man-made artifice, not naturally occurring
• Constructive - serving a useful purpose, to solve some problem
• Actionable - can be acted upon, processed by humans and machines

As indicated in the Miller definition above, metadata helps people find resources and determine their value, for whatever need is at hand. This function of metadata is especially critical in digital environments, where humans rely on computer processing for reliable and timely results:

• Metadata facilitates organization, indexing, discovery, access, analysis, and use of print and online resources.
• Metadata enables software agents to navigate and "comprehend" web content.
• Metadata influences search engine results, rankings, and click-through rates.
• Metadata is even more important for non-textual content that isn't readily processed by machines (e.g. images, multimedia, datasets).
• Metadata presence and quality (or the lack thereof) can significantly help or hinder time and money expenditures in research activities.