A common source of angst among metadata reviewers as well as metadata creators and editors, keywords are subject to a number of misconceptions. Our purpose here is to help clarify the issues and reduce the angst.
Keywords as categories for which your data are relevant
Subjects about which your data have something to say
Things you measured
Places where you made your measurements
Methods by which you measured or observed things or analyzed your observations
Aspects of the data package, format, contents, or documentation that, compared with other data, might be similar to some and not to others
Problems for which your data might be seen as a helpful resource
Names of things with which you want your data to be associated
Types or names?
Keywords can be types or names, but people will associate many different ideas with named things: