Does it means whites of English ancestry or does it mean elite whites of English ancestry that belong to mainline churches but not fundamentalists?
If we use the former definition, Kentucky, say, would be a lot more "WASP" than Connecticut, but if we use the latter Connecticut would be more "WASP."
It's also interesting how census responses have a regional and class basis to them. In New England and among the affluent, people are more inclined to declare English ancestry while in the South, they're more likely to say "American."
Scotch-Irish identity seems to be a Southern working class and rural phenomenon. Though I should add the so-called "Celtic thesis" is garbage.
Whites with roots in New England
are more likely to be of English ancestry than whites with roots in the South and Appalachia, whose ancestors more likely came from the southern part of Scotland or from what is now Northern Ireland.