My young child I used nightly reading to him as observation about his level. I gaged his comprehension and interest and even ability to decode (randomly I would get a tickle in my throat and would need for him to read a page out loud while I drank water. I usually read one chapter and said good night. Sometimes the next morning the book was done and if I wanted to know the end I needed to finish it by myself. Sometime his behavior let me know he wasn't ready for a book level. He wouldn't stay awake for The lion, witch and the wardrobe in the summer after first grade. I was sure if we read it together he would read the rest of the series by himself. But I over estimated his readiness. Two years later a teacher recommended the series and he devoured them and pretended that I had never suggested them.