Our Sputnik Moment: Descartes
Log on to https://reports.nwea.org or maximize the logon/menu site. Select DESCARTES under DATA-TOOLS. Select the subject, the concept or strand, the RIT range of your focus group. It gives you the content you need below, at and above the student's RIT range. There is an appendix for content vocabulary and symbols for each range.
This is the kind of data mining and analysis used in business and now these same techniques can be used for teaching. Grouping is done by the Class Breakdown by Rit report, and the Descarte reports provide the differentiated education goals for each student or group.