In a blog post from this summer, Dr. Timothy Shanahan writes,
So why is the common core making such a big deal out of having kids read hard text?
One of the most persuasive pieces of evidence they considered was a report, Reading: Between the Lines, published by American College Testing (ACT; 2006).
You can view the summary or download the full ACT report right here.
In Reading: Between the Lines, ACT demonstrates that student performance cannot be differentiated in any meaningful way by question type. Students do not perform differently if they are answering literal recall items or inferential items (or other question types like main idea or vocabulary, either). Test performance, according to ACT, is driven by text rather than questions. Thus, if students are asked to read a hard passage, they may only answer a few questions correctly, no matter what types of questions they may be. On the other hand, with an easy enough text, students may answer almost any questions right, again with no differences by question type.
Dr. Shanahan, a member of the CCSS development team, has some particularly interesting insights into the thinking behind the standards. In the video above, watch him speak about the shift from a skills-focused approach in state standards to the emphasis on complex text in the Common Core State Standards.