What Is the Plural of Datum?
The plural of datum is data. In formal, scientific, and academic writing, datum refers to a single piece of information, measurement, or observation. When you have more than one such piece, you use data. However, in everyday conversation and much modern writing, data is often treated as a singular mass noun (like “information”), which can cause confusion. This guide explains the correct plural form, when to use each version, and how to avoid common mistakes.
Quick Answer
- Singular: datum (one fact, one measurement)
- Plural: data (multiple facts or measurements)
- Formal use: “The datum is accurate.” / “The data are reliable.”
- Informal use: “The data is ready.” (acceptable in many contexts)
Understanding Datum and Data
Datum comes from Latin and is the singular form. It is most commonly used in technical fields like surveying, engineering, statistics, and scientific research. For example, a single GPS coordinate is a datum. In everyday English, you will rarely hear someone say “datum” unless they are being very precise or working in a specialized field.
Data, the plural, is far more common. The key question is whether you treat data as a plural noun (taking a plural verb) or as a singular mass noun (taking a singular verb). Both are used, but the choice depends on your audience and context.
Formal vs. Informal Tone
Formal / Academic / Scientific Writing
In formal contexts, especially in peer-reviewed journals, technical reports, and academic papers, data is treated as a plural noun. You should use plural verbs and pronouns.
- Correct: “The data are collected from three experiments.”
- Correct: “These data support the hypothesis.”
- Correct: “Each datum was recorded separately.”
Informal / Everyday / Business Writing
In emails, casual conversation, and many business contexts, data is treated as a singular mass noun. This is widely accepted and often sounds more natural.
- Acceptable: “The data is ready for review.”
- Acceptable: “This data shows a clear trend.”
- Acceptable: “We need more data to make a decision.”
Nuance: If you are writing for a strict academic audience, use plural verbs with data. If you are writing a business email or a blog post, singular verbs are fine and often preferred for readability.
Comparison Table: Datum vs. Data
| Feature | Datum (Singular) | Data (Plural – Formal) | Data (Singular – Informal) |
|---|---|---|---|
| Number | One | More than one | More than one (treated as a mass) |
| Typical verb | is, was, has | are, were, have | is, was, has |
| Example | This datum is incorrect. | These data are incorrect. | This data is incorrect. |
| Common in | Technical, scientific, formal | Academic papers, formal reports | Emails, conversation, business |
| Frequency of use | Rare in everyday speech | Common in formal writing | Very common in all contexts |
Natural Examples
Here are examples you might hear or write in real situations.
Formal / Scientific
- “The datum from the first sensor was corrupted, so we excluded it.”
- “All data are stored in a secure database.”
- “Each datum represents a single patient’s blood pressure reading.”
Informal / Business Email
- “The data is attached. Please review it before the meeting.”
- “We have enough data to move forward with the project.”
- “Can you send me the data from last quarter?”
Conversation
- “I checked the data, and it looks fine.”
- “How much data do we have on this?”
- “That datum seems off – let’s double-check it.” (rare but possible in a technical discussion)
Common Mistakes
- Using “datums” as the plural of datum. This is incorrect. The plural is data, not datums. (Exception: In surveying, “datums” can refer to multiple reference points, but this is very specialized.)
- Mixing singular and plural verbs inconsistently. If you choose to treat data as plural, be consistent throughout your document. Do not write “The data is collected and then they are analyzed.”
- Using “datum” when you mean multiple items. “I have three datums” is wrong. Say “I have three data points” or “I have three pieces of data.”
- Forgetting that “data” can be singular in informal contexts. Some strict editors still insist on plural verbs for data, but in most real-world writing, singular is acceptable.
Better Alternatives and When to Use Them
If you are unsure whether to use datum or data, or if you want to avoid the confusion altogether, try these alternatives:
- “Data point” – Use this instead of datum in most situations. It is clear and modern. Example: “Each data point was recorded.”
- “Piece of data” – Another clear singular form. Example: “This piece of data is important.”
- “Information” – If you are referring to data in a general sense, information is always singular and avoids the issue. Example: “The information is ready.”
- “Results” or “findings” – In research contexts, these words can replace data when appropriate. Example: “The results show a significant difference.”
When to use it: Use datum only in formal, technical, or scientific writing where precision is required. In all other cases, use data (as singular or plural depending on your audience) or one of the alternatives above.
Mini Practice: Test Your Understanding
Choose the correct word or verb form for each sentence.
- The (datum / data) from the experiment (is / are) conclusive.
- Each (datum / data) was checked for errors.
- We have collected enough (datum / data) to publish.
- This (datum / data) point is an outlier.
Answers:
- data / are (formal) OR data / is (informal). Both are acceptable depending on context.
- datum (singular, formal)
- data (plural or singular – both work)
- data (because “data point” is a common phrase)
Frequently Asked Questions
1. Is “data” singular or plural?
Technically, data is the plural of datum. In formal writing, it is treated as plural. In informal and business writing, it is often treated as singular. Both are correct in their appropriate contexts.
2. Can I use “datums” as a plural?
Only in very specialized fields like surveying or geodesy, where a “datum” is a reference point. In general English, datums is not correct. Use data or data points instead.
3. Should I use “these data” or “this data”?
Use “these data” in formal, academic, or scientific writing. Use “this data” in informal, business, or everyday writing. Choose based on your audience.
4. What is the plural of “datum” in a sentence?
Example: “The datum is correct.” (singular) → “The data are correct.” (plural, formal) or “The data is correct.” (plural, informal).
Final Note
Understanding the plural of datum is about knowing your audience and context. In formal writing, stick with data as a plural noun. In everyday communication, feel free to use data as a singular mass noun. When in doubt, use data point or piece of data for clarity. This small distinction can make your writing sound more natural and professional.
For more help with tricky plurals, visit our Common Plural Forms section or check our FAQ for quick answers. If you have a specific question, feel free to contact us.
