Is Data Singular or Plural?

“The data was analysed” or “the data were analysed”? This question comes up in almost every academic manuscript, and the answer depends on your style guide, your discipline, and your journal.

The debate exists because “data” is a Latin word. In Latin, “datum” is singular and “data” is its plural form. Traditionally, academic English preserved this distinction: “this datum shows” (one data point) and “these data show” (multiple data points). But language evolves, and “data” is increasingly treated as a singular mass noun (like “information” or “evidence”) in everyday English and in some academic fields.

The Traditional Academic Convention: Data Is Plural

In most academic writing, “data” is treated as plural. “The data were collected over a six-month period.” “These data suggest a positive correlation.” “The data are presented in Table 3.”

This is the convention in APA style, in most scientific journals, and in formal British academic English. If you use “data” as plural, you will never be flagged by a reviewer for getting it wrong. It is the universally safe choice in academic writing.

The singular form “datum” is rarely used in practice. Instead of “this datum shows,” most writers say “this data point shows” or “this observation shows.”

The Modern Alternative: Data as a Mass Noun

In computing, data science, business, and general usage, “data” is increasingly treated as a singular mass noun, like “information.” “The data was analysed.” “The data shows a trend.” This mirrors how most English speakers actually use the word in conversation.

Some journals and style guides accept this usage. The Guardian and The Economist style guides both treat “data” as singular. Some computing and engineering journals accept singular usage. If your target journal uses “data” as singular in its own published articles, you can follow that convention.

However, many academic reviewers and editors still consider singular “data” to be incorrect in formal academic writing. Using it creates a risk that may not be worth taking.

What to Do in Your Manuscript

Check your target journal. Search for “data” in three or four recently published articles and note whether the journal uses “data were” or “data was.” Follow whatever convention the journal uses.

If you are writing a thesis, check your university’s style guide. If no preference is stated, use the plural convention. It is the traditional academic standard and the choice that no examiner will question.

Whatever you choose, apply it consistently. “The data were collected in Phase 1” on page 5 and “the data was analysed in Phase 2” on page 12 is an inconsistency that reviewers and editors will flag. Pick one convention and use it from the first page to the last.

Related Words

“Media” (plural of “medium”) and “criteria” (plural of “criterion”) follow similar patterns. “The media are reporting…” (traditional plural) vs “the media is reporting…” (modern singular). In academic writing, “criteria” should always be treated as plural: “the criteria were met.” The singular form is “criterion”: “one criterion was not met.”

“Appendices” is the plural of “appendix” (in the academic sense). “Analyses” is the plural of “analysis.” “Hypotheses” is the plural of “hypothesis.” These Latin and Greek plurals are standard in academic writing and should be used correctly.

For a broader overview of grammar conventions in academic writing, see our English grammar review for non-native researchers.

Conclusion

Treat “data” as plural in academic writing unless your journal explicitly uses singular. “The data were analysed” is the safe default. Be consistent throughout the manuscript. And if in doubt, remember: no reviewer has ever rejected a paper for treating “data” as plural.

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Further Reading

• Overall English Grammar Review for Non-Native Researchers
• A Quick Guide to Punctuation
• The Correct Way to Use “Respectively” in a Sentence
• What Is Academic Writing in Research?

Frequently Asked Questions

Does APA style treat “data” as singular or plural?

APA treats “data” as plural: “the data were analysed,” “these data suggest.” This is the convention in APA 7th edition. If your journal uses APA style, use the plural form consistently throughout your manuscript.

Is it wrong to write “the data was analysed”?

Not necessarily. Some journals and style guides accept singular “data,” particularly in computing and data science fields. However, many academic reviewers consider it incorrect in formal writing. The plural form (“the data were analysed”) is always safe. Check your target journal’s convention.

What is the singular of “data”?

“Datum” is the singular form, but it is rarely used in modern academic writing. Most writers use “data point” or “observation” instead. “This datum shows” is technically correct but sounds archaic. “This data point shows” is more natural in contemporary usage.

Are there other Latin/Greek plurals I should know for academic writing?

Yes. “Criteria” (plural of “criterion”), “hypotheses” (plural of “hypothesis”), “analyses” (plural of “analysis”), “appendices” (plural of “appendix”), “phenomena” (plural of “phenomenon”), and “media” (plural of “medium”). Using the singular form where the plural is needed (e.g., “the criteria was met” instead of “the criteria were met”) is a common error.