Should one write “The data are [show, demonstrate, etc.]…” or “The data is [shows, demonstrates, etc]…”?

In Latin, the word data is a plural noun and the singular form is datum. In today’s English, the word data is usually used as both singular or plural (as are many other plural Latin nouns such as “opera” and “media”). Find out which usage is more common in your field. If articles that you read for your own work treat data as singular (e.g., if the verb indicates that the word is singular, as in “The primary data is listed in Appendix A”), then use it as singular in your own writing. If articles that you read for your research often treat data as plural (e.g., “The data are compelling” and “One single datum is clearly an outlier”), then you can write in this manner if you like.