“To Kill a Mockingbird” is worth 15 points.

Librarians and teachers report that students will almost always refuse to read a book not on the Accelerated Reader list, because they won’t receive points. They base their reading choices not on something they think looks interesting, but by how many points they will get. The passion and serendipity of choosing a book at the library based on the subject or the cover or the first page is nearly gone, as well as the excitement of reading a book simply for pleasure. This is not all the fault of Renaissance Learning, which I believe is trying to help schools encourage students to read. Defenders of the program say the problem isn’t with Accelerated Reader itself, but with how it is often implemented, with the emphasis on point-gathering above all else. But when I looked at Renaissance Learning’s Web site again this summer, I noticed the tag line under the company name: “Advanced Technology for Data-Driven Schools.” That constant drive for data is all too typical in the age of No Child Left Behind, helping to replace a freely discovered love of language and story with a more rigid way of reading.

Not long ago, I went back and re-reread three of my own favorite books of all time, books that made me into a writer. They introduced me to my heroines, girls who grew up in real hardship in vibrantly rendered landscapes that I had never seen before. Anne, in “Anne of Green Gables,” made me understand friendship and “kindred spirits” and imagination. Francie, in “A Tree Grows in Brooklyn,” made me ache at the injustice of having a charming alcoholic father (his suit drying green after he falls into the bay while fishing) and a mother who cannot love her as much as she loves her more handsome brother. And Nel, the quieter half of the inimitable pair of friends in “Sula,” made me feel the way girls love each other intensely in childhood, captured in the precise and lovely language of lines like this: “We were two throats and one eye and we had no price.”

Total points for my three favorite books: 49.

Many teachers say Accelerated Reader has increased reading among students, who like the process of collecting points and the prizes schools sometimes give to students who collect the most. I have certainly seen the excitement at my daughter’s former elementary school when winners were announced. But as a writer and mother of three girls who love novels, I find the idea that we can apply a numerical formula to reading a bit insulting to literature. I’m not against all quantifying. But as Renaissance Learning itself emphasizes, Accelerated Reader’s formula cannot measure “literary merit for individual readers.” It cannot consider emotion and landscape and character, and certainly can’t identify what makes even some of the simplest-seeming sentences so complex and lovely and painful.

How can we really measure this passage about Helen Burns, the companion in “Jane Eyre” who will shortly die of tuberculosis? “. . . a beauty neither of fine color, nor long eyelash, nor penciled brow, but of meaning, of movement, of radiance. Then her soul sat on her lips, and language flowed.”

“Jane Eyre” is worth 33 points.

And nothing can measure how a young life can be changed by literature. It can be a small change — like understanding more about someone from a different race or period or culture — or a complete change, as happened to me when I read the stories of Anne, Francie and Sula and decided I could be a writer, so that people would know my own world.