Cassie Hemphill: But this depends on the situation. Is he presenting individual pieces of data (e.g., five different spreadsheets) or a single piece of data (e.g., one spreadsheet combining the results of the five individual spreadsheets)?

Jennifer German: Plural, but not common and it should be. It is more precise.

G. Miki Hayden: One doesn't want to sound like a fool.

L. L. Thrasher: Nobody knows what a datum is. Save it for scientific reports.

John Russell: Once again common usage must override Latin and in this case although plural, data is normally collected into a lump or singular form when discussed but not when analysed by a math guy.

Yocheved Golani: Same rule and preference for mass nouns as stated above.

Clyde Linsley: I like both, actually.

Lisa Karam Middleton: Data is plural, no matter how it sounds.

Elayne Cree : Data can be either plural or singular, depending on what it refers to. If it's a body of information, it's singular. If it's discrete bits, it's plural.

Dennis McCarthy: If data means information, I'd use is. In this sentence, the data sound more like bits of information so I like "are" better.

Charlotte Fox Luttrell: Data is a collective noun.

Mark H. Bloom: See above.

Amy Goldyn: Use as a collective noun when referring to a unit.