When you walk into a bookstore or glance at books online, one of the first descriptors you will see is the genre labeled with an audience age. Young Adult, Middle Grade, Adult, New Adult. You initially feel forced to go to the section that matches your age or the age of the reader you are buying for. The guidelines must mean that the books there will be a perfect fit and there is no reason to stray to the other categories. Right?
Originally, I assumed audience age was all based on the calculated reading level of the book. I believed that there was a formula that you could put the book criteria in and out would pop the audience age. I was naive and foolish. In fact, even understanding reading levels can be complicated. The reading level for books can be listed by grade level (Flesch-Kincaid), guided reading, Lexile level, DRA level, or reading recovery. You can look up the conversion tables online to see how all the different reading levels interact with each other to assist librarians and readers in picking out a book that is at the proper reading level.
But the reading level isn’t a magical equivalency for audience age. An example I found online showed that Earnest Hemmingway’s books were written for an elementary school (grade 4-5) reading level. Last time I checked though, fourth graders aren’t checking out Farewell to Arms or For Whom the Bell Tolls for their reading time. Another example, Twilight, came out when I was in Middle School. The reading level is calculated at grades 3-5. The interest level at 9-12. But here we were, 7th-grade girls smack dab in the age range for middle grade, and we are all reading this book. Heck, based on the way Edward, Bella, and Jacob jumped up the baby name list in 2006, the book was insanely popular among adults!
So why is Twilight and For Whom the Bell Tolls both labeled as YA? Two of the easiest criteria you see tossed around is the age of the protagonist (rule of 3) and the issues dealt with in the book.
Twilight is easier to identify. The protagonist is a teenage girl, so the main character is a similar age to the audience. She faces issues similar to those faced by other teenagers, like having to change schools, making new friends, figuring out high school politics, and dealing with crushes.
But For Whom the Bell Tolls follows around Professor Robert Jordan, who although described as young, is definitely not a teenager. He decides to go fight in a war in a different country because of his own ideological dealings. Not exactly a decision made by most teenagers.
So that brings us to the other criteria: themes, language, plot complexity, length, and style. The more complex the themes and the language, the older the target audience is going to be. If the characters curse, you can guess that the book is going to be labeled as YA or higher, although I know plenty of middle-grade kids who can string together words that would make a prison warden blush. The same goes for graphic violence, sex, and drug use, although these can be issues facing younger readers, those books tend to get a 14+ YA or Adult label.
The issue with these other criteria is that they are pretty arbitrary. One person could label a book as YA, another as NA, and a third as just plain A depending on their personal criteria and social bias. A book could be a fit for ages 9 to 99 and still be assigned to a narrow audience age.
So what does it mean? It means read whatever you want. The label on the shelf does not define who will enjoy the book or who should be reading it. Adults can enjoy young adult books. Middle-grade readers can enjoy adult books. There is no reason to judge anyone for the section of the bookstore or library they are browsing.