Not that we educators are really dummies, but for those who are clueless on what the Common Core has to say about using "rich text" in the classroom, here is one of the best overviews that I have seen. NYC is a behemoth and therefore uses their resources to efficiently reach a great number of teachers. Once again, they have created a wonderful tool available to the nation. Click here to view.
They speak that the 3 key points in Appendix A for consideration when determining whether a text passage is appropriate for "rich text" classroom usage are:
Quantitative measures (algorithmic measures of complexity)
Qualitative measures (more subject to the teacher's appraisal (What is the vocabulary of text? What is the content - does it relate, enhance, build knowledge, etc.) View the rubric in this video at this link. It is one of the better tools I have seen. Some of the considerations evaluated in the rubric are: layout; purpose and meaning;
knowledge demands length? background knowledge required level of reasoning required & more.
Considerations of the reader and the task - What can you ask the students to do with this data? Can they investigate? Can they debate, dialogue, discuss, react, quote, generate further questions for investigation? Can I couple this passage with any of the "Power Verbs" below?
Whether you are a novice or expert in understanding the theme of rich text, this video and the rubric are worth investigating. See you school librarian for help in finding examples on how to mine for rich text, how to search for great primary sources freely available, or where to look on the web for resource within databases correctly lexiled for your classroom. (See older posts below on Lexiles, Mining for Rich text and more.)