Illustrating text complexity

To help illustrate the importance of weighing quantitative complexity equally with qualitative complexity, Appendix A uses The Grapes of Wrath as an example.  Many widely used qualitative measures such as the Lexile Framework and Flesch-Kincaide Grade Level Test rate this novel as appropriate for grades 2-3.  This counterintuitive result emerges because works such as The Grapes of Wrath often express complex ideas in relatively commonplace language (familiar words and simple syntax), especially in the form of dialogue that mimics everyday speech.

This is an excellent document that illustrates how to determine text complexity in literary and informational text:

A Beginner's Guide to Text Complexity