Q: I work for a population research organization in Washington. I wonder which of these phrases are correct: 1) “Children by household head’s educational (or “education”) attainment,” and 2) “Per-pupil educational (or “education”) expenditures adjusted for regional cost differences.”
A: Both “educational” and “education” can perform the function of adjectives. When the noun “education” is used as an adjective, it’s called an attributive noun.
But just because a noun can be used attributively as an adjective doesn’t mean it’s always appropriate to use the noun that way. Sometimes a straight adjective (like “educational”) is better.
In the first phrase you’ve asked about, we’d recommend the straight adjective (“educational attainment”).
Why? Because we’re speaking here of an attainment that’s “due to, or arising from, education,” to use the Oxford English Dictionary’s definition of “educational.”
But in the second phrase either the straight adjective or the attributive noun would be fine to modify “expenditures.”
Our preference, though, would be for “education expenditures.”
Why? Because the expenditures are for education – they aren’t in themselves educational.
As you can see, however, the choice between a straight adjective and an attributive noun is quite often a judgment call.