Data: Singular or Plural (Style Guide)
Whether you write “data is” or “data are” depends on what you mean and on the rules of your field or publication. Use “data are” for separate observations when that is the required convention; use “data is” for data treated as a body of information when the style allows it. Keep agreement consistent throughout.
One small verb can make a research sentence sound out of step with its field. Yet there is no single rule that works for every use of data. The word began as a plural form, but today many writers also use it as a singular word for information as a whole. The right choice depends on meaning, audience, and the style rules you need to follow.
What does “data” mean in your sentence?
Data can refer to separate facts, measurements, or results, or to information considered as one body. That difference often guides verb choice. When the word points to individual items, plural agreement is a natural fit. When it means information collectively, singular agreement may be acceptable, depending on the style and field.
The word data comes from the plural of the Latin word datum. In many scientific and technical settings, writers still use it as a plural noun. For example: “The data are consistent across trials.” Here, data means multiple results, and are agrees with that plural meaning.
In everyday English, data is also often treated as a mass noun, like information. A mass noun refers to something considered as a whole, rather than as separate countable items. In that sense, “The data is stored in the archive” may be acceptable when the relevant style permits singular use.
Think about what the sentence highlights:
- Separate observations or measurements: “The data show a clear difference.”
- A collective information resource: “The data is available online.”
These are useful patterns, not universal rules. A journal or department may ask for plural agreement even when the sentence treats data as a whole. Check the requirements before you edit.
Which style rule should you follow?
Data has more than one accepted agreement pattern, so the governing style matters. For academic and professional writing, check the assigned style manual, journal instructions, or department policy first. If no rule is given, consider your field’s usual practice, your intended meaning, and the need to use one pattern consistently.
Start with the instructions that apply to the work in front of you. A journal may give a specific rule. A course or thesis guide may name a style manual. If so, follow that authority rather than relying on a broad claim about what “all academic writing” requires.
If no instructions address data, look at writing from your field. Scientific and technical writing often keeps the plural form when referring to results or measurements. General English, and some writing that treats data as a body of information, may use singular agreement. Practices vary, so avoid assuming that one department’s preference applies everywhere.
A practical order of checks is:
- Read the journal, course, or institutional instructions.
- Check the relevant style manual if one is required.
- If guidance is silent, review recent writing in the same field or publication.
- Choose the form that matches your meaning and keep it steady.
When a choice remains uncertain, ask your instructor, editor, or advisor which convention they expect. That is more useful than arguing that one form is always correct.
How do you keep agreement consistent?
Agreement means that the words in a sentence match in number. If you use data as plural, use plural verbs and related words. If you use it as singular, use singular forms throughout. A sentence can sound inconsistent when its verb, pronoun, or demonstrative points to a different meaning.
The verb is only one part of the sentence to check. Demonstratives such as this and these, and pronouns such as it and they, also signal whether you are treating data as singular or plural.
| Intended use | Example | Agreement pattern |
|---|---|---|
| Separate results | “These data are consistent across trials.” | These + are |
| Separate results | “The data show a change.” | Show |
| Information as a whole | “This data is stored securely.” | This + is |
| Information as a whole | “The data is available in the archive.” | Is |
Avoid mixing the patterns without a clear reason. For example, “The data is incomplete, and they need review” pairs singular is with plural they. If you mean one body of information, revise it to “The data is incomplete, and it needs review.” If you mean separate results, use “The data are incomplete, and they need review.”
Also check which noun is actually the subject. In “The data set is complete,” the subject is set, which is singular. The presence of data does not make the whole subject plural. This distinction can prevent unnecessary edits.
How can you edit a sentence about data?
A reliable edit starts with meaning, then checks the applicable rule, and ends with a consistency review. Do not change is to are just because data has a plural history. First decide whether the sentence refers to separate items or a collective resource, then apply the style expected for that document.
Use this four-step check:
- Identify the meaning. Are you describing separate measurements, responses, or findings? Or are you referring to information as a whole?
- Check the required convention. Follow the journal, course, or department rule when one is provided.
- Match every related word. Check the verb, demonstrative, and pronouns.
- Review the whole document. Search for data and make sure your choices are consistent unless the meaning changes.
The examples below are editing scenarios, not claims about a particular study or publication.
| Draft sentence | What to check | Possible revision |
|---|---|---|
| “The data is consistent across all trials.” | Are you describing separate trial results? Does the style require plural agreement? | “The data are consistent across all trials.” |
| “These data shows a steady rise.” | These is plural, but shows is singular. | “These data show a steady rise.” |
| “This data are in the archive.” | This is singular, but are is plural. | “This data is in the archive,” if singular use is allowed. |
| “The data set are complete.” | The subject is set, not data. | “The data set is complete.” |
| “The data is incomplete; they need review.” | Singular is conflicts with plural they. | “The data are incomplete; they need review,” or “The data is incomplete; it needs review.” |
If changing the sentence makes the meaning less clear, consider rewriting it. For example, “The measurements are consistent” may be more precise than “The data are consistent” when you specifically mean measurements.
What are common mistakes to avoid?
Most problems come from treating one usage as the only correct one, or from changing one word without checking the rest of the sentence. A careful edit respects the document’s rules and the writer’s intended meaning. These checks also help prevent a local correction from creating a new mismatch elsewhere.
- Calling singular use always wrong. Singular data is established in general English when it means information as a whole, though a specific style may require plural use.
- Calling plural use outdated or incorrect. Plural agreement remains common in scientific and technical writing and may be required by a publication.
- Using a blanket rule for every field. Conventions differ across disciplines, publishers, and institutions.
- Checking only the verb. This/these and it/they need to match the chosen sense too.
- Changing agreement without checking the subject. In “The data set is ready,” set controls the verb.
- Switching patterns randomly. Keep one pattern in a paper or project unless the meaning genuinely changes.
A quick search for data before you submit can reveal mixed forms. Review each result in context rather than using a global replace: some sentences may refer to individual observations, while others refer to a whole information resource.
What should you remember?
The choice between data is and data are is about meaning and convention, not a simple test with one answer for every sentence. Use the required style first. If the style is silent, choose the form that fits your intended meaning and your field, then check agreement across the full sentence and document.
For separate measurements, plural agreement often makes the relationship clear: “The data show…” For information treated as a whole, singular agreement may fit: “The data is…” Use the pattern your venue expects, and avoid mixing forms without a reason.
Frequently asked questions
These short answers cover the most common questions about singular and plural data. They do not replace a journal’s or institution’s instructions, which may set a specific house style. When you are editing a paper, use these answers as a starting point, then check the rules for your audience.
Is “data” singular or plural?
It can be either. It is traditionally plural, but it is also widely used as a singular mass noun meaning information.
Should I write “the data is” or “the data are”?
Use the form required by your style guide or publication. If no rule is given, choose based on meaning and field convention.
Is “data is” grammatically correct?
It can be correct when data means information as a whole and the relevant style accepts singular use.
Is “data are” grammatically correct?
Yes. Plural data is standard in many scientific and technical contexts, especially when it refers to separate observations or results.
Is “this data” correct?
It can be correct when data is treated as a singular mass noun. If you use plural data, write these data.
Should I use “data shows” or “data show”?
Use data show for plural agreement. Use data shows only when data is treated as singular and the style permits it.
What is the singular form of “data”?
Datum is the traditional singular form, especially in technical contexts. In everyday writing, people often use data as a mass noun instead.
Can I use both “data is” and “data are” in one paper?
Use one pattern consistently unless the meaning clearly changes or your style guide directs otherwise. Search for every use of data during editing.
(This article was written by one of our staff writers, Alan Westbrook. Visit our Meet the Team page.)
