I invite you to review Is it Time to Drop Finding the Main Idea. From the article,
Reading tests are really knowledge tests in disguise,” says Daniel Willingham, a cognitive psychologist at the University of Virginia and author of the book The Reading Mind: A Cognitive Approach to Understanding How the Mind Reads.
The article references The Famous Baseball Study where it was discovered a student with lower reading skills who knows a lot about baseball does better on assessments than a 'stronger' reader who knows less about baseball. Is background knowledge more important than finding a main idea? If so, how do we change our PD for reading instruction?