I'd also say that it depends on the context. If you're talking about 'a set/amount of data', 'data' is often used as shorthand for that, and should either be expanded to the full phrase or used in the singular. If you're clearly talking about multiple items without a clear set-description being implicit, it should be in the plural.
I'd also say that it depends on the context. If you're talking about 'a set/amount of data', 'data' is often used as shorthand for that, and should either be expanded to the full phrase or used in the singular. If you're clearly talking about multiple items without a clear set-description being implicit, it should be in the plural.