Lexercise practice is designed to establish a foundation for true mastery (above 80% accuracy) for reading and spelling single words and for reading and writing connected text.

One of the best and most rigorous ways to monitor progress toward true mastery is through spelling, such as in the Whiteboard Spelling Procedure. 

Spelling is harder than reading so students who can consistently spell a pattern correctly can generally read words with that pattern accurately and fluently.  

Reference

Binder, C., Haughton, E., Bateman, B. (2002). Fluency: Achieving True Mastery in the Learning Process. Professional Papers in Special Education, University of Virginia Curry School of Education.    Retrieved 5-30-10