2. The method of claim 1 , wherein, for an input text passage: an automatic determination is made as to whether the text passage is an informational passage or a literary passage; a difficulty estimate is computed for the text passage using the informational text scoring model when the text passage is an informational passage; the difficulty estimate is computed for the text passage using the literary text scoring model when the text passage is a literary passage; and the difficulty estimate is outputted.
7. The method of claim 2 wherein the difficulty estimate is highly correlated with difficulty classifications deemed to be true.