As of 2018, this is still the appropriate list of ProQuest subject headings. If the list changes, those changes will be reflected on this guide.
What if I do not know what words to choose?
Think of this as your opportunity to make your work discoverable to researchers. Think of the words you would use if you were searching for your paper in a database.
Choose the subject headings that most broadly describe your field of study and your research topic. Remember, the more terms you use, the more discoverable your work is likely to be. Keywords are not required, but, if you choose to use them (remember-you want your work to be discoverable!), you should choose words that most closely describe your research topic. It is a good idea to look at keywords used by other authors to describe your topic, including those used in your cited sources, in order to choose words that will lead others to your research.