I wanted to confirm which of the options would be correct here. My brain can find reasoning for both.

Reason for "were":

  1. The sentence could be rephrased as "Orion data and Crew Dragon data were added.", in which I'd use were since there are two names ("Orion data" and "Crew Dragon data").

Reason for "was":

  1. I may be wrong in this, but I think that "Orion and Crew Dragon" can work as a modifier to "data". In this case I'd use "was", since the subject would be "data".

I think both of them might be valid choices, but I'd like to confirm.

  • 1
    'Data', I notice, is now being treated as plural. It used to be regarded as a singular. I cannot quantify or tabulate this. I have just noticed it in documentaries and news items.
    – Nigel J
    Commented Jun 19, 2020 at 12:12
  • 1
    You'd say salt and fresh water were added, so it should be were. (Unless Orion and Crew Dragon data is a single thing, like clean and clear water.) Commented Jun 19, 2020 at 12:43
  • 1
    Fresh water and salt is a good suggestion. If you want to keep the same order, you could say Salt was added, along with fresh water. Commented Jun 19, 2020 at 13:54
  • 2
    @NigelJ "Data" is plural, it is the plural of "datum". If indeed the use of it as a singular word is going out of fashion that is merely a return to its technically correct usage. Not that long ago people were arguing against the use of "data" as a singular noun and getting quite hot under the collar about it.
    – BoldBen
    Commented Jun 19, 2020 at 19:50
  • 1
    And while we are on that subject, the plural of spacecraft is spacecraft.
    – Phil Sweet
    Commented Jun 19, 2020 at 20:24

2 Answers 2


Data is a confusing word, because sometimes it's treated as a plural, and sometimes as a mass noun. See the discussion in Merriam-Webster. If you're treating it as a plural, you clearly should use were. But even if you're treating it a mass noun, you should use were. You'd say that

salt and fresh water were added,

so it should be were.

On the other hand, if Orion and Crew Dragon data was a single thing, like

clean and clear water,

then it would be was.



Orion data and Crew Dragon data were added.

This is because at least two data were added: one datum from Orion crew and one datum from Crew Dragon.

If you were using adding a single point (a datum), you would say:

The Orion temperature datum was updated for last Monday.

Here is the APA Style guide (6th ed) with a blog that backs up this distinction:

To help clear up any confusion regarding the proper use of these terms, I list examples of datum and data being used correctly below:

Each datum matches the location of an object to a coordinate on the map.

Although we have compiled the results, these data are the focus of another report and are not described here.

On the other hand, datum seems to be dying out (in American English, at least). If it were only one piece of data being discussed, it's not uncommon to hear:

Crew Dragon data was added.

  • Data was plural in Latin. So was agenda. But Latin isn't English. Nobody says the agenda for this meeting are ... Commented Jun 20, 2020 at 17:15
  • @PeterShor . Please note that I cited a contemporary AP Style blog, so there is at least one person who can contradict your "nobody" assertion. Also note that I acknowledged in the last paragraph that "datum seems to be dying out." When I was an editor, we maintained the datum/data subject-verb agreement because it was indicated in our style guide, CMoS. And I think your argument for Latin origins may fall apart if you think Marshall McLuhan was wrong to say "The medium is the message." It grates on my ears to hear speakers and writers confuse one medium with many media.
    – rajah9
    Commented Jun 21, 2020 at 11:12

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