Range of Readers in 1 Classroom

For any teacher it is critical to recognize that in any given classroom, the range of reading ability is approximately 2/3 of the students’ chronological age. This means that in a classroom of mostly 15 years old, the range of reading ability, and “inability” across the class will span 10 years!

In other words, within one seemingly heterogeneous class, the most at risk students could have a 5th grade reading level and the most advanced students could have a 15th grade reading level.

From Professional Learning Board’s online continuing education course for teachers: Reading Across the Curriculum