Is Datum Singular or Plural?
Yes, datum is singular. It refers to a single piece of information, a single measurement, or one fact. The plural form of datum is data. In formal, technical, and academic writing, this distinction is still observed. However, in everyday conversation and informal writing, data is very often used as a singular mass noun (like “information”). This guide will help you understand when to use datum and when to use data, so you can write with confidence in medical, scientific, and professional contexts.
Quick Answer
Datum is singular. Use it for one fact, one measurement, or one point of information. Data is the traditional plural. Use it for multiple facts or measurements. In informal English, data is often treated as singular (e.g., “The data is clear”), but in formal medical and scientific writing, treat data as plural (e.g., “The data are consistent”).
Detailed Explanation
The word datum comes from Latin, where it means “something given.” In English, it has kept its Latin singular and plural forms. This is similar to other Latin-derived words like criterion (singular) and criteria (plural), or phenomenon (singular) and phenomena (plural).
In medical and scientific writing, precision matters. If you are referring to a single blood pressure reading, a single lab result, or one observation, datum is the correct word. If you are referring to a collection of readings, results, or observations, data is the correct word.
Formal vs. Informal Tone
Formal tone (academic papers, medical journals, research reports): Use datum for singular and data for plural. This is the standard in peer-reviewed literature and formal medical writing.
Informal tone (emails to colleagues, casual conversation, blog comments): Using data as a singular mass noun is widely accepted. For example, “The data shows a trend” is common in everyday speech. However, if you want to sound careful and precise, especially in a professional email, using data as plural is safer.
Email and Conversation Context
In a formal email to a supervisor or a research team: “The datum from the morning test is abnormal. The data from the full week are being analyzed.” This shows you understand the distinction.
In a quick conversation with a colleague: “Do you have that datum handy?” or “Can you check the data on that?” Both are fine, but the second is more common.
Comparison Table: Datum vs. Data
| Feature | Datum (Singular) | Data (Plural) |
|---|---|---|
| Number | One | Two or more |
| Example | One blood pressure reading | A set of blood pressure readings |
| Formal use | “This datum is an outlier.” | “These data are statistically significant.” |
| Informal use | Rare in conversation | “The data is ready.” (singular verb) |
| Common in | Medical reports, research notes | All contexts |
Natural Examples
Here are examples you might actually hear or write in a medical or professional setting.
- In a lab report: “Each datum was recorded at the same time of day.”
- In a team meeting: “We have one datum that doesn’t fit the pattern.”
- In an email to a colleague: “Could you double-check that datum from the patient’s file?”
- In a research paper: “The data were collected over six months.”
- In a presentation: “These data suggest a new approach.”
Common Mistakes
Even experienced writers sometimes make these errors. Here are the most frequent ones.
- Mistake: “The datum are correct.” (Using a plural verb with a singular noun.)
Correction: “The datum is correct.” - Mistake: “The data is clear.” in a formal paper.
Correction: “The data are clear.” (In formal writing, keep the plural verb.) - Mistake: “I have many datums.” (Using an English plural ending on a Latin word.)
Correction: “I have many data points.” or “I have many data.” - Mistake: Using “data” as singular in a medical journal.
Correction: Most medical journals require “data” to be treated as plural. Check the style guide of the journal you are submitting to.
Better Alternatives and When to Use Them
If you are unsure whether to use datum or data, you can often rephrase the sentence to avoid the issue entirely. This is especially helpful in informal writing.
- Instead of: “This datum is important.”
Say: “This single measurement is important.” - Instead of: “The data shows…” (informal)
Say: “The information shows…” or “The results show…” - Instead of: “These data are…” (formal)
Say: “This set of data is…” (using “set” makes the verb singular and avoids the plural issue.)
When to use “datum”: Use it in formal medical writing, research notes, or when you want to emphasize that you are talking about exactly one piece of information. It is also useful in technical fields like surveying, engineering, and statistics.
When to use “data” as plural: Use it in academic papers, medical journals, and any formal context where precision is expected.
When to use “data” as singular: Use it in emails, conversations, blog posts, and other informal writing. It is widely accepted and sounds natural.
Mini Practice: Test Yourself
Choose the correct word to complete each sentence. Answers are below.
- This single _____ (datum / data) needs to be verified.
- The _____ (datum / data) from the study are conclusive.
- Can you send me that one _____ (datum / data) point?
- All the _____ (datum / data) is stored in the system. (informal context)
Answers: 1. datum, 2. data, 3. datum, 4. data
Frequently Asked Questions
1. Is it ever correct to say “datums”?
In general English, no. The plural of datum is data. However, in very specific technical fields like surveying and GIS (geographic information systems), datums is used to refer to multiple reference points or coordinate systems. This is a rare exception.
2. Should I use “data is” or “data are” in a medical report?
In a formal medical report, use “data are.” Most medical journals and style guides (like AMA and APA) treat data as a plural noun. In an internal email or a quick note, “data is” is acceptable.
3. Is “datum” still used in modern English?
Yes, but mostly in formal, technical, and academic writing. In everyday conversation, people almost always say “data point” instead of “datum.” For example, “Let me check that data point” is much more common than “Let me check that datum.”
4. What is the difference between “datum” and “data point”?
They mean the same thing: one piece of information. “Data point” is more common in modern English, especially in business and technology. “Datum” is more formal and traditional. You can use either, but “data point” is safer in most contexts.
Final Note
Understanding the difference between datum and data is a mark of careful writing. In medical and scientific fields, using the correct form shows attention to detail. In everyday writing, you have more flexibility. The key is to match your word choice to your audience and context. For more help with medical plurals, explore our guides on Singular or Plural Checks and Common Plural Forms. If you have questions, visit our FAQ page or contact us.
