What is Metadata?

Recently I have been asked this question many times. By coincidence, Bonnie Swoger wrote an article in Scientific America Online and asked that same question. And so … what is metadata? Well, the most common answer I find in library related sources is that metadata is “data about data”. When I tell this to people who aren’t librarians, they just stare at me blankly. The reason is that most have no idea what “data about data” means. This is one of reasons I enjoyed Bonnie’s article on metadata. Her comment that she also gets blank stares when she mentions “metadata” is just too familiar not to be funny. The other reason I enjoyed her article is the focus on the everyday aspect of metadata and why metadata is important.

What is metadata? Metadata is information that helps you uniquely describe and contextualize a resource. If you use a library, metadata is the information that appears on your screen when you search for a book. This display provides information on the title of the book, the author, date of publication, number of pages, or a summary. If you are a fan of buying items online, the information displayed by that vendor (be it Amazon, Apple, Sears, etc.) is metadata. Typically, online stores will provide the name of the article, who it is made by, the date it was made, and a brief summary. Another example is when you take a picture with your phone or camera. Many cameras today automatically insert what is called a date/time stamp on the picture. A date/time stamp is simple the date and time when the picture was taken. This date and time are metadata.

Another important aspect of metadata that Bonnie highlights is that metadata is “structured” information. If we just provided information about a resource without any organization to that information, it would be hard to understand that information. For example, let’s say I provided this metadata information:

  • cookie, blue box jar, Dr. Tardis who, cookies, makes authentic noises talking

Obviously there’s some information missing. But I also don’t know what this information is referring to on several different levels. I don’t know what item this metadata information is trying to describe. I also don’t know what type of information is being conveyed to me as in what is the title or designation of this item. Is it the Dr. Who or blue box or talking Tardis blue box [from] Dr. Who?

To help us read metadata information more easily in an organized or structured way, metadata information is organized by metadata tags, sometimes referred to as elements, fields, or labels. If I go back to my example, structured metadata information through the use of metadata tags looks like:

  • Title: Dr. Who Tardis talking cookie jar
  • Description: Blue box for cookies that makes authentic noises

Already, thanks to the use of metadata tags, we have a much better idea of what this item is. For all those Dr. Who fan’s, here’s an image.

This image is even information about the actual resource.

What I’ve added to Bonnie’s definition of metadata is that metadata is structured information to “uniquely” describe and contextualize a resource. If you are going to take the time to describe a resource, most likely you want people to be able to distinguish it from other like resources. Any bit of information that sets an item apart from others can and should be included in the metadata information. For my example above, unique metadata information would be:

And here I know what this item is, where to buy it and how much it is…all thanks to metadata.

Why is metadata information important? Bonnie’s answer is spot on. Without metadata, discovery of resources would be that much harder and in some cases impossible. Think of images. If you had absolutely no metadata information to describe and contextualize that picture, you wouldn’t know anything about it unless you took the picture and happened to remember what it was about. Another way to think of this is that a resource would most likely be lost. Going back to the library example, many people don’t know about the hidden treasures in libraries. The reason is that there’s no associated metadata. These treasures are sitting in a room somewhere — lost and lonely.

Metadata information can be created automatically or by a person. It does take work to create metadata information that uniquely describes a resource. However, it is well worth the effort because then we can discover and learn or buy appropriate holiday gifts :)…