It has been hailed as the largest and most systematic experimental evaluation of educational practices in the US.  It compared  more than a dozen models for teaching entering elementary students the basics of reading, language, and math.  A clear winner emerged and the results have been swept under the rug.  This product includes the findings from Abt Associates plus three (3) technical reports from the Direct Instruction Model at the University of Oregon.  Very rare.  Spiral & Paperback manuals, good condition.  Sold as a full set.