Dr. Seuss's Green Eggs and Ham was read by just 16 percent of kindergarteners and first-graders

An update on the emerging impact of Common Core on reading in schools: How the Common Core made Kafka way more popular by Libby Nelson.

The list of stories, poems, and nonfiction near the end of the Common Core state standards isn't supposed to be an assignment list. But teachers seem to be using it that way.

The standards, now used by 44 states, spell out what students should learn and learn how to do at each grade level. Near the end is a 13-page, single-space list of books, poems and plays.

The list, called Appendix B, is meant only to give an idea of the type of works students should be reading in order to meet the standards; middle-schoolers aren't required to read The Adventures of Tom Sawyer, but teachers should choose books at a similar level of difficulty or with similar themes.

The list is having a big influence. A new study finds that nearly every book on the Common Core list is more likely to be read than it was a few years ago.

Many naysayers are concerned that recommending books necessarily means other books will not get read. However, there is some really interesting information about the diversity of reading in American classrooms.

The list is a very long way from providing a unified canon used in most American schools. Even the most-read book at any grade level — Dr. Seuss's Green Eggs and Ham — was read by just 16 percent of kindergarteners and first-graders, the Renaissance study found. Books that saw the biggest popularity boost are generally still read by less than 2 percent of all students.