Posted by Richard on UTC 2015-10-14 15:22.
The data used by this study is incomplete.
The grammar pedants are reeling in shock: 'Ha, Ha! This bozo doesn't know that data is the Latin plural of datum and therefore requires a verb in the plural! It should be data were'.
Well, I reply, this bozo does indeed know that, and probably a lot of other Latin that the average grammar pedant doesn't. Currently, however, this bozo is writing English, not Latin.
English usage distinguishes between objects that are countable, such as bottles, and things that are not, such as water. Countable nouns can have plurals; uncountable nouns, for obvious reasons, can't. This difference is reflected in a number of ways in the context in which these nouns appear: how many bottles of water; how much water etc.
Native speakers of English, even if they have never seen the principle stated in writing, rarely have problems with this usage. Well, of course, sloppy speech between illiterates can produce all kinds of perversions of the language, but that's why we call it sloppy speech. Even subtleties such as waters, as in her waters have broken or the waters covered the earth we take in our stride. The average native speaker of English distinguishes without the need for thought between money (uncountable) and units of money such as dollars or pounds (countable).
Despite this general ease of use, at the margins of the subject, where forms are changing continually, things can get a bit wild. In traditional English damage is an uncountable noun: The damage is considerable. More and more, influenced by American English, which in turn is probably influenced by the European languages of the USA's early immigrants, we hear the new plural, damages are. German or French speakers are happy with Schäden (pl. of Schaden) or dommages (pl. of dommage).
Surprisingly, even one of the great uncountable words, information, is starting to succumb to foreign influence, which accepts and expects Informationen (DE) and informations (FR). I would say that at the moment, most native speakers would find informations unacceptably strange when used in English. How and how quickly this will change in the future? Who knows?
So what to do with that word data, dreamed up by our learned Latinists? In the mind of a native English speaker the word is an equivalent of information. Not exactly equivalent, in that it implies an empirical or measured source for this information. But all problems disappear when we treat data as we treat information. But then, the pedants cry, what do you call a single bit of data, a datum? Ha, that's got you, bozo.
Well, when I come to that hurdle I will jump it, because I have never – never – read or heard any native speaker needing a word for a single atomic bit of data. In such cases the unpedantic native English speaker would say a measurement.  I exclude hereby all scientific papers written by Germans struggling to translate from Datum/Daten and getting tangled up in date and dates. I've read quite a few of those. Correspondingly, the unpedantic native German speaker would say Messung, as in eine einzelne Messung liegt ausserhalb dem erwarteten Bereich.
So, when this bozo reads the data are he knows that the people writing are either grammar pedants or are damaged, rule-following personalities who have sat at the feet of grammar pedants and breathed deep of their noxious vapours.
In fact, using data as a countable is not even pedantry: it's just wrong. And what is worse, it is un-English! You will be wanting to call The Marriage of Figaro an opus  next…