The New York Times reports on a new service from online book-seller Amazon.com. The software, called Text Stats, reportedly lets readers compare different written works–from classics by Shakespeare and Hemingway, to children’s books and even the King James Bible–by culling the full text to determine how many times a particular word or phrase appears throughout the book. The software then uses an index system to rank the book for ease of reading and clarity, the paper said. Such statistical models often are used by teachers to determine the grade-level appropriateness of certain books. Some critics, however, say the system is flawed. Though Text Stats and other programs like it can count words and make connections based on statistical models, they say, the software lacks the human touch necessary to understand an author’s motivations.