Writing to Read: Evidence for How Writing Can Improve Reading is a report available from the Carnegie Foundation, part of the Carnegie Corporation of New York, the very group responsible for the Writing Next and the Reading Next reports. (All the aforementioned reports are from the Alliance for Excellent Education)
Here is text linked to more information on the report.
Washington, D.C., April 14, 2010--Although reading and writing have become essential skills for almost every job, the majority of students do not read or write well enough to meet grade-level demands. A new report from Carnegie Corporation of New York and published by the Alliance for Excellent Education (the Alliance) finds that while the two skills are closely connected, writing is an often-overlooked tool for improving reading skills and content learning.