High school science textbooks are more difficult and less accessible to readers than high school English textbooks -- but both are simpler than the average newspaper article. So says Cornell University professor emeritus Donald Hayes, who used a computerized system he developed, called LEX, to analyze the level of difficulty of textbooks. The higher the LEX score, the harder the book.

• For instance, the New England Journal of Medicine has a LEX score of 26, while Time magazine scores 1.6.

• High school science texts get a -0.5 score, which means they are slightly easier to read than a newspaper.

• High school English texts get a -22.3 score, indicating they are much less difficult to read than, for instance, USA Today.

The answer is not to dumb down science books, says Hayes, but to get students reading more difficult texts sooner.

Source: Maribel Villalva, "The Science of Reading," USA Today, February 23, 2000.