Singular and Plural Forms in Scientific Writing

In most cases, forming the plural in English is relatively simple (just add an 's'). However, authors frequently make a few mistakes when forming plurals, especially with mass nouns.

Count nouns are discrete, individual entities -- items that you can count. Mass nouns, sometimes called uncountable or non-count nouns, refer to an undifferentiated mass or collection of material. For example, you would not say, “I'm all out of a water.” It is correct to say “I need a little water” or “I need a few bottles of water.” In this example, water is a mass noun, and bottle is a count noun. Likewise, when describing an experiment, you would quantify a mass noun by adding a specific measurement (e.g., “2 ml of water”); in fact, whether you choose bottles or milliliters, the mass noun requires some unit of measurement to be quantified. Note that the unit is plural and the mass noun ('water') remains unchanged.

Data and research are two nouns that are frequently used in the sciences and are much more tricky than they appear.

It is often taught that data (like media or spectra) is a plural word (the singular is 'datum'). In most contexts, the word data refers to specific numerical results and should therefore be treated as a plural count noun, with a corresponding plural verb form.

• The patient data are sorted in Table 1.
• Data were collected retrospectively from patient medical records.

However, this rule is not strict; it depends on the scientific context. Data can sometimes be used in the singular as a mass noun. For example, in Ars Technica, Chris Foresman examines how securely “user data is stored” by Apple's iCloud service. Likewise, the following PLOS ONE article uses the singular form of data in its title: “Clickstream Data Yields High-Resolution Maps of Science.” In computer science, data is often used in the singular form as an mass noun; that is, computer scientists use the word data to describe a mass of information to be accessed, stored, or processed (information is another great example of a mass noun).

Unlike data, research should always be used as a mass noun, and its verb must be singular. Some writers attempt to force research to take a plural form (researches); however, this usage is incredibly rare, and it will almost certainly trouble a reviewer. Because research is a mass noun, it can refer to a wide body of literature (e.g., “current research in the field”) or the work involved in a specific project (e.g., “our research focused on the following objectives”). If you need to quantify the research in question, try using study/studies (e.g., “In total, 28 studies were included in this review”). Consider the following examples, also from PLOS ONE:

• A Comparison of rpoB and 16S rRNA as Markers in Pyrosequencing Studies of Bacterial Diversity
• Aggregating, Tagging and Integrating Biodiversity Research (not researches)

We hope these tips and examples help avoid the grammatical confusion that often surrounds data and research. Are there other singular or plural forms that cause you trouble in your scientific writing? Write to [email protected], and we will work with you to find the answer. Best of luck!