Leveled Readers

Leveled readers are reading texts that have been rated as to their difficulty. U.S. teachers of literacy use leveled readers to guide literacy learners through ascending levels of difficulty in the texts they attempt to read on their own. It has been found (citation) that this improves motivation.

There are several systems for scoring reading texts. A correlation table can be found here http://www.readinga-z.com/guided/correlation.html. A paper describing the history of scoring reading material and assessing two such systems is found here: http://www.ciera.org/library/reports/inquiry-1/1-010/1-010.pdf