"After all, the ECLS data don't say that books in the house cause high test scores; it says only that the two are correlated."
The above sentence is from Freakonomics, a book well worth reading. My question is, Shouldn't "it" be "they"? Or, if one wants to keep "it," then "don't" should be "doesn't."
Not a teacher
The confusion is generated by "data" being the plural of "datum". Although scientists refer to it in the plural, the modern tendency is to treat it as a mass noun, thus being the the singular applicable. Both are classified correct but does, indeed, generate some difficulties when refering to it as an antecedent.