The Short Answer: Both Can Be Right
Use “data is” when you mean information as a whole: “The data is stored securely.” Use “data are” when you’re treating data as individual facts or measurements: “The data are inconsistent.” Neither is automatically wrong. Your audience, the kind of writing you’re doing, and any style guide you follow should decide which sounds right on the page.
That answer may disappoint anyone hoping for a grammar rule they can enforce with a red pen. But it gives you something better: a way to make a deliberate choice.
Why Does “Data” Have Two Options?
The word data came into English from Latin as the plural of datum. If you’re treating it as that traditional plural, it takes plural verbs:
The data are available.
The data show a sharp increase.
But English speakers also use data as a mass noun—a word for something considered as a whole, like information. In that use, it takes singular verbs:
The data is available.
The data shows a sharp increase.
A database might hold thousands of separate entries, yet you can still talk about its contents as one body of information. That’s the distinction behind the two verb choices. Oxford’s entry for data recognizes both uncountable and plural uses, while noting that the plural is used in technical English.
So the Latin origin explains “data are.” It doesn’t make “data is” an error. English has a habit of borrowing words and then letting them settle into new roles. If you enjoy that sort of grammatical plot twist, Uncover Words has more in its look at English’s unusual plurals.
When “Data Is” Sounds Natural
For most everyday writing, “data is” is a comfortable choice. You’ll often see it in discussions of computer files, customer information, storage, privacy, and other situations where data means information collectively.
Your data is backed up every night.
The survey data is ready to download.
How much data is left on my phone plan?
That last example offers a useful clue. We say “how much data,” just as we say “how much information.” In that sentence, we aren’t counting separate data points; we’re talking about an amount.
The singular approach also has a place in professional writing. The Microsoft Style Guide, for instance, calls for a singular verb with data. Its preference is a house style, though—not a rule every writer has to follow.
When “Data Are” Fits Better
“Data are” is particularly at home in research and technical writing, where a writer may be thinking about separate observations, results, or measurements.
These data are from three separate experiments.
The data show that the samples behaved differently.
The data were collected over six months.
Notice “these data.” It belongs with the plural treatment. If you choose “these,” continue with a plural verb: “These data are,” not “These data is.”
A preference for the plural is not just theoretical. The UK’s Office for National Statistics discussed the choice and decided to continue treating data as plural in its writing. That differs from Microsoft’s singular-verb style. The two organizations aren’t using different dictionaries; they’re making different editorial choices for their work and readers.
Of course, “data are” doesn’t automatically make a sentence more scientific. If the data is weak, a plural verb won’t rescue the conclusion.
How to Choose Without Overthinking It
If you’re staring at a sentence and both versions look plausible, run through these questions:
- Are you following a style guide? Use its preference. That matters more than winning a general argument about data.
- Are you writing for a specialist audience? Check the conventions of the publication or field. Plural data is familiar in some research settings, but don’t assume every technical audience wants it.
- Are you treating data as a body of information or as separate observations? “The data is encrypted” suits the first idea; “These data are inconsistent” suits the second.
- What have you used elsewhere in the piece? Unless you have a clear reason to switch meanings, keep your verbs, pronouns, and words such as this or these consistent.
That last point is easy to miss. A paragraph that begins “The data are incomplete” and ends “It is stored in the archive” changes its treatment of data halfway through. You could keep it plural—“They are stored in the archive”—or recast the second sentence: “The dataset is stored in the archive.”
For a broader refresher on matching subjects with verbs, see Uncover Words’ guide to subject–verb agreement.
The Words Around “Data” Matter Too
Choosing is or are is only part of the job. Nearby words should agree with the version you’ve chosen:
| Treating data as a whole | Treating data as plural | |---|---| | This data is useful. | These data are useful. | | The data shows a pattern. | The data show a pattern. | | The data has been checked. | The data have been checked. |
The most noticeable combinations to avoid are “these data is” and “this data are.” They ask the reader to treat data as plural and singular at the same time.
Also, “The data shows a pattern” and “The data show a pattern” express the same basic idea. The verb difference tells readers how you’re treating the noun; it doesn’t, by itself, say how many measurements you have.
What About “Datum”?
Datum is the traditional singular form. You may encounter it when someone needs to identify one particular reference point or piece of information. For an ordinary email or article, though, “one data point,” “one measurement,” or “one piece of data” will usually tell readers what you mean more readily.
And no, you don’t need “datas” to talk about more information. Say “more data,” “several data points,” or “multiple datasets,” depending on what you mean. The Oxford dictionary, for example, gives datum as the singular in technical use and includes “one vital item of data” as another way to refer to an individual item.
Sometimes the Best Answer Is a Different Noun
Still torn? Rewrite the sentence around a more specific word. This isn’t dodging the grammar question; it can make your meaning clearer.
The dataset is incomplete.
The measurements are incomplete.
The information is incomplete.
The results are incomplete.
Each sentence identifies what you’re actually discussing. A dataset is one collection. Measurements are separate items. Information is treated as a whole. Results are individual findings.
One caution: don’t swap these words as though they mean exactly the same thing. Results may be conclusions or outcomes, while data may be the information used to reach them. Choose the noun that fits the facts.
The Final Verdict
“Data is” and “data are” are both valid. For general writing about information collectively, “data is” will often feel natural. For writing that treats data as separate observations—or follows a plural-only style—use “data are.” Then make the rest of the sentence match: this/is/shows or these/are/show.
The goal isn’t to prove you remember your Latin. It’s to write a sentence your readers can follow without stopping to argue with the verb.