WHETHER "data" is singular or plural is one of those hardy perennials of usage debate in which both sides have impossibly entrenched positions. Or so I had thought, but the Wall Street Journal has, as of today, taken an unusually fence-sitting position:  

Most style guides and dictionaries have come to accept the use of the noun data with either singular or plural verbs, and we hereby join the majority.

As usage has evolved from the word’s origin as the Latin plural of datum, singular verbs now are often used to refer to collections of information: Little data is available to support the conclusions.

Otherwise, generally continue to use the plural: Data are still being collected.

(As a singular/plural test, try to substitute statistics for data: It doesn’t work in the first case — little statistics is available — so the singular is fails to pass muster. The substitution does work in the second case — statistics are still being collected – so the plural are passes muster.)

I admire the attempt to satisfy both tradition and change, but it does leave some leeway that I can imagine many writers having a hard time handling.  People crave hard and fast rules: they don't have time to make judgments all the time, like the suggested route of substituting "statistics". (This is the first time I've heard of this remedy, for what it's worth.)

But hard-and-fast doesn't always work, as I noted in my last submission on "data".  We don't use the foreign morphology of every word brought from a foreign language. But we do sometimes.  Since that last post, I have found this excellent one supplying some new counterarguments against always-plural "data".  Among them: we certainly don't use "agenda" and "stamina" in the plural, though they have come to us the same way "data" has. (If your boss ever does say "moving on to the next agendum", let us know.)  The "media" question remains mixed: some have it singular, others have it plural.

We have a strong urge to just have language behave, but regular readers of this column know that, as the original Johnson knew, it just won't. He wrote that "to enchain syllables, and to lash the wind, are equally the undertakings of pride." Less well known, but perhaps more to the point, he pointed to the unruliness of language as the sign of a healthy culture constantly enriching itself:

The language most likely to continue long without alteration, would be that of a nation raised a little, and but a little, above barbarity, secluded from strangers, and totally employed in procuring the conveniencies of life; wither without books, or, like some of the Mahometan countries, with very few: men thus busied and unlearned, having only such words as common use requires, would perhaps long continue to express the same notions by the same signs, But no such constancy can be expected in a people polished by arts, and classed by subordination, where one part of the community is sustained and accommodated by the labour of the other. Those who have much leisure to think, will always be enlarging the stock of ideas, and every increase of knowledge, whether real or fancied, will produce new words, or combinations of words. When the mind is unchained from necessity, it will range after convenience; when it is left at large in the fields of speculation, it will shift opinions; as any custom is disused, the words that expressed it must perish with it; as any opinion grows popular, it will innovate speech in the same proportion as it alters practice.

Aside from the casual slur of the "Mahometan countries", this remains realistic good sense, as does the rest of the essay, much recommended.