You can’t win with data. When you use it as a singular noun—e.g., this data is, which might sound more natural to nonscientists—you may lose credibility with some readers. When you use it as a plural noun—e.g., these data are—it may sound odd to readers who are used to hearing data as a singular noun.
Origins of the data controversy
Data was originally the plural form of datum, a Latin noun meaning a thing given. Both words were relatively rare in English until modern times, and not until the late 19th century did English-speakers, especially scientists, begin using data in the sense in which it’s used today. For as long as data/datum has been used in this sense, some writers writers have treated data as a plural count noun, and some have treated it as a mass noun.
In general, fighting to preserve proper Latin grammar in modern English is a lost cause. Though data was originally a Latin word, it has now been in English for centuries, so we can think of it as an English word derived from the Latin, in which case, Latin grammar rules need not be taken into account. What matters now is how English-speakers use the word. And the trouble with data is that there is a minority who strongly feel—with some logical justification—that the majority are wrong.
Other words have gone through similar transformations. Agenda, for example, was originally the plural form of agendum, but the latter word faded out of common usage long ago. Unlike data, though, agenda is used as a singular count noun in English, its plural being agendas.
data usage
So, should we use data as singular or plural? It comes down to preference, and you can’t be faulted for using the one that sounds better to you (though no doubt some readers will vehemently disagree with us on this). In general, data is still treated as plural in scientific and academic contexts, and it’s usually treated as singular in nonscientific contexts.
Usage varies across major publications. Here are a few examples:
Japan Economic Data Worsen [Wall Street Journal]
GDP Data Shows Japan’s Economic Growth Slowing [LA Times]
The data is culled quarterly from approximately 27 million randomly sampled . . . [Washington Post]
Money data are not everything . . . [Telegraph]
