Using a proficient OST to PST conversion tool you could successfully resolve many critical OST file corruption issues. Such application offers an interactive GUI and recreates the corrupt exchange OST file into fresh Outlook PST files. The utility renders a successful OST email recovery procedure that securely restores all mail data.
This is a handy chart to easily convert DRA, Guided Reading & AR levels with grade level equivalencies as well as reading development stages. The color coding is a system I used to label my books in first grade and found it especially handy when I was a reading specialist.