To answer the question of whether we should use “these data” or “this data”, we first need to consider what we are referring to. Data is any factual information, such as figures, statistics, or measurements that are grouped for calculation, analysis, or reasoning.
The word data is the plural form of the Latin word ‘datum’, which is a piece of information or “given thing” for use in calculations or analysis.
Now we know what we are dealing with, let’s look at the correct grammar.
Should I use “These Data” Or “This Data”?
In the rules of Latin and English grammar, data is a plural noun. Based on this, the correct grammar should be the traditional “these data”, in much the same way as you might refer to “these animals” or “these days”.
Data is a plural term but with the singular form datum rarely, if ever used and the absence of an s or es that would usually indicate the plural, it can seem slightly odd, even to a native English speaker. If we’re following the traditional rules of grammar, we shouldn’t use “this data” but opt for the traditional “these data”.
However, as the singular datum is seldom used, the English language has evolved and the word “data” is now more commonly used to describe pieces of information gathered to form a whole, so data is subsequently treated as an unaccountable mass.
As a result, it is common to find the vast majority of people using “the data shows”, “this data” or “early data indicates”.
Words such as water, money, research, and bread are also unaccountable nouns. For example, if we want to specify an amount of water we use a suitable measurement such as a liter, body of water, or glass. You wouldn’t use “waters”.
As with bread, you wouldn’t say “breads”, you would use loaves of bread, loaf, or slices.
This can be confusing even to native English speakers, as data in its true form as a plural noun is still favored by purists and commonly used in scientific or academic text. So, when you hear a professor or statistician talk, they will often opt for the traditional “these data”.
However, in modern English, data is now widely considered to be unaccountable, which allows for the more commonly used “this data”.
Both versions are ok, you just need to pick your team. In spoken English and for general use “this data” is absolutely fine. However, if you are a grammar purist, then “these data” is for you – especially if your writing or field of work or study requires the traditional approach.