In English Grammar: Meryn Stol voted up this answer. Eric Pepke "Data" isn't a singular noun. It never was. It has become a mass noun. Mass nouns take singular verb forms but never the indefinite article. You can easily tell that people don't use "data" as singular, because nobody ever says "a data." I don't understand why other people don't seem to notice this; it seems pretty obvious and clear. Maybe it's because pedants used to go around saying "'Data' is plural, not singular," thus displaying their ignorance. Mass nouns refer to things that are measured by quantity, not number, either because it looks homogeneous or the numbers are too big to bother counting exactly. You say "a gigabyte of data" just like you say "a liter of water." You don't write out the exact number of bits or Avogadro's number. Back in the day, you had to write down every damn datum, and when you had them written down, they were data (plural). Look, there are 100 data, and boy does my hand hurt. Now you just... - Meryn Stol