Problems often arise for non-native English language users when they try to apply the rules that they used to learn English to everything that they encounter later on. Languages are always evolving, often this is a uniform way that conforms with common rules, but sometimes they evolve to push everyday usage away from the rules that they were built upon. Professional writers use style guides to help to write in a uniform way for specific readers or publications. However, in some cases even these exhaustive guides can't help!
Data is a pluralised noun from datum, a singular noun. So, it stands to reason that the word 'data' should be used in a plural form. So, 'the data were analysed' is corrected usage of the word, right? I can imagine many native speaker ears bleeding at the sound of that sentence when it's read out loud. Generally, the native speaker always wants to use 'data' as a singular word. Does this mean that they are incorrect?
Today's use of the word 'data'
Let's face it, the word 'datum' is all but extinct. It's a word that is very rarely used and has almost completely lost its connection with its pluralised brother 'data'. Today, we use the word 'data' as if it isn't countable despite its ancient connection with its almost dead brother.
Which is accepted usage, data as a singular or plural?
Both are accepted usage of the word. Although, the argument still continues amongst English language 'die-hards' who require some form of clarity on the issue. The Guardian newspaper, a UK publication that publishes its own respected style guide, wrote about the issue in this article. This article reveals many views on this subject by a range of respected English language institutions.
The Guardian ended the article with this statement by the maintainer of their own style guide:
It's like agenda, a Latin plural that is now almost universally used as a singular. Technically the singular is datum/agendum, but we feel it sounds increasingly hyper-correct, old-fashioned and pompous to say "the data are".
Shortly after the Guardian issued that statement the Wall Street Journal also commented on the issue by saying:
The Wall Street Journal has made a new ruling on the data/plural debate - and it now matches the Guardian's style guide too.
How should you use the word?
The jury is still out on this subject as the argument continues, but there are some simple points to take from this debate. Firstly, it's widely accepted that it is correct to use 'data' as a singular or plural noun. Secondly, 'data' in the plural form is regarded as 'dated' by some, but it isn't by others, so consider your audience and make your decision based on that. Although, it's advisable to stick with the plural form for academic writing, because it is a very precise formal-style of writing.
Just know that when the word 'data' is used, mere grammatical rule does not apply!