So is data singular or plural?
The only people who get really upset about this question are those who insist it is plural — ‘the data are clear’ rather than ‘the data is equivocal’. Their argument is that data, in Latin, is plural, and datum is singular, like media and medium, stadia and stadium, currilcula and curriculum, etc. This is true, but we don’t speak Latin. When was the last time you heard anyone pluralize stadium by talking about stadia rather than stadiums? No one talks about a datum; they may refer to a datapoint, but they are more likely to talk about a piece of data, just as they would refer to a member of a team, therefor I argue that data, like team, is a collective singular.
So who is right? Which is correct? Ask me again in 50 years when usage will have settled the issue. Meanwhile, use the version you like, and cast your own vote in the usage contest, unless of course the person telling you to do it the other way is a teacher who can flunk you, or a boss who can fire you. This is not the hill you want to die on.